Ugly Tomatoes

Standard

Cat-facing on a heritage Beefsteak tomato: ‘Big Beef’. Photo: MJ Guilbault

Question: There is something wrong with my tomatoes and I don’t know the cause, so I’ve sent you a photo. The plants appear healthy, so it’s probably a pest. Is this something you’ve seen before? If so, what should I do?

MJ Guilbault

Answer: This is a condition called cat-facing because the deformity is sometimes said to resemble a cat’s face … something I would certainly take umbrage with if I were a cat! It’s a physiological condition, not a transmissible disease nor are insects usually involved, although fruit damaged by insects can sometimes develop similar scar tissue.

Dimples, lines of scar tissue… yep, it’s cat-facing! Photo: http://www.eatortoss.com

The problem occurs when the fruit is inadequately pollinated. This causes parts of the fruit to develop more quickly than the rest, leading to dimpling and cracking and that results in scar tissue. Often the damage originates at the blossom end of the fruit. Subsequently, however, diseases or insects can take up residence in the openings, giving the impression that they are the cause.

Cat-facing is generally linked to abnormal temperatures, either too hot or too cold, both of which prevent normal pollination. When temperatures above 86 ° F (30 ° C) or below over 55 ° F (13 ° C) occur just as the flower is opening and ready for pollination, that can lead to pollen that sticks poorly to the stigma. That’s one reason cat-facing often seems it to appear a few weeks after a cold spell or a major heat wave.

Other factors involved are irregular watering and excessive nitrogen-rich fertilizer (one where the first of the three numbers on the fertilizer label is greater than the others).

Note that the cat face is generally limited to extra-large tomatoes, especially Beefsteak, and to heirloom varieties. It is rarely seen in cherry tomatoes or modern tomatoes of more modest size.

Yes, You Can Eat Ugly Tomatoes

Yes, you can eat this tomato…. but I suggest removing the scar tissue first. Photo: photos.hgtv.com

Fruits suffering from cat-facing remain edible and tasty: you just have to remove the scar tissue with a knife, which adds a bit of extra work to their preparation. Ugly tomatoes have little market value, though.

Prevention

This problem is most easily avoided by choosing varieties that are resistant to it … and that would include most tomatoes other than Beefsteak tomatoes and some of the heritage varieties, so you have plenty of choice. 

If big, beefy tomatoes are your thing, though, one way you can help reduce the problem is by delaying planting tomatoes outdoors in the spring until the soil and air are warmer: over 55 ° F (13 ° C).

There isn’t much you can do about extreme summer heat, other than to mulch. Mulch helps keep the soil cooler and therefore tomato roots as well.

Mulch also helps keep soil more evenly moist and that also helps prevent cat-facing. It further helps if you don’t wait until the leaves wilt before watering and, when you do water, if you water thoroughly. Quick, shallowing watering will only make things worse.

You can pollinate tomato flowers with your electric toothbrush. Photo: laidbackgardener.blog

Finally, anything that will help ensure thorough pollination will be useful. For example, you can also plant a wide range of pollinator-friendly flowers near your tomatoes or pollinate the tomato flowers yourself with an electric toothbrush if you’re not seeing a lot of bumblebee action. And likewise avoid the use of insecticides that are harmful to bees and other pollinators.


Cat-facing: it’s easy to avoid … unless you just can’t live without those huge Beefsteak tomatoes!

An Apple Tree Overloaded With Fruit

Standard

When an apple tree bends, it could break! Photo: Indie452, reddit.com

Question: I have a 5-year-old apple tree that is currently chock full of apples. However, it’s begun heavily leaning to one side due to the weight of the fruit. Do I need to stake it?

Martine DB

You can use a forked branch as a crutch to hold a branch up. Photo: Rustica

Answer: That’s one possibility. Another is to use one or two solid forked branches (harvested elsewhere) as crutches, lifting and bracing the heaviest branches.

However, before carrying out either step, have you considered thinning the fruit?

Orchard owners do this on a regular basis. The idea is to remove excess fruit, the weight of which can cause the trunk or branches to bend or even tear off. Also, when apples are too dense, the fruits stay smaller and are more prone to disease and insects. As well, when the tree bears too much fruit, many apples end up aborting and falling off anyway as the summer goes on.

Also, by “lightening” the tree of its excess fruit, you can help increase production next year. You see, many apple trees naturally produce biennially: a year of abundant harvest is usually followed by a year with few to no fruit. But by reducing the load in a year of plenty, the tree often invests the energy thus saved in better flowering and fruiting the following season. By repeating this thinning during years of mass production, it’s often possible to attain a more reliable annual production.

Thinning excess fruit is even more important in the case of young trees, like yours, whose thinner branches are more prone to breakage.

How to Thin Apples

With your fingers or pruning shears, simply remove the excess fruit by pulling them free or clipping them at their base. Just don’t damage the spur they grow from.

Thin out clusters of apples, leaving one healthy fruit. Photo: gardening.which.co.uk

Often, there are clusters of 5 or 6 fruits. It’s best to reduce the cluster to just one fruit, two for crabapples. Keep the largest fruit, probably the fruit produced by the central flower of the cluster, unless it’s damaged in some way: insects, disease, physical injury, etc. In that case, choose a smaller but healthy fruit instead.

Next, give the whole branch a look-over: if it still appears heavy, remove more fruit, leaving about 6 to 8 inches (15 to 20 cm) between the remaining apples.

Ideally, you’d do this when the fruits are still small, within a month of fruit formation, but even if you missed that window, thinning out could still help prevent breakage.

A Bit of Pruning

It is also possible that the leaning trunk is partly caused by uneven branching. If there are many more branches on one side of the tree than on the other, it will tend to lean even if the fruit load is reasonable. If you feel this might be the case, you can also lighten the tree by removing a few branches from the overloaded side to better balance the weight. True enough, you don’t normally prune apple trees in the middle of summer, but this is an exception and the pruning is relatively minor. 

Early next spring, when the tree is barren, take a closer look and consider whether more pruning is needed.

Staking

After you’ve thinned the tree, it’s really time to consider whether the trunk is still necessary. If it’s still leaning, it probably is.

There are several ways to stake a tree, but the most logical way of staking an established tree is to use guy wiring (taut cables) to straighten the trunk. 

💡Helpful Hint: Guy wire kits are readily available in garden centers and hardware stores.

Here is one possible method.

Careful staking can straighten the tree out. Ill.: Ooreka.fr

Hammer 3 stakes into the ground, evenly distributed around the trunk, so they lean outwards like a tent peg. A distance of about 5 to 6 feet (1.50 to 2 m) from the trunk would be fine.

Used flat material around the trunk that won’t dig in, like these straps. Photo: extension.umn.edu

Now install 3 ropes or wires around the trunk just above the first fork of the tree. These wires or ropes must never come in direct contact with the trunk or branches, as over time they will dig in and cause damage. You need some sort of broad, flat material to cover the bark: canvas strapping, strips of old carpeting, burlap or bicycle inner tubes would be fine. Do not insert ropes or wires through sections of garden hose to wrap around the tree stem. You see this done a lot … but the hose, being round not flat, will put all its pressure on a very narrow strip of bark and can thus cause damage.

💡Helpful Hint: Consider painting the stakes orange and using colored rope to make both more visible and prevent tripping.

Secure the other end to the stake and tighten it, adjusting it as needed to straighten the tree. The trunk should still be able to move in the wind to a certain degree: movement actually helps solidify it.

Staking should not be left in place for more than two years; otherwise it can weaken the tree. At any rate, if the tree hasn’t returned to its proper upright form after 2 years, it never will!


With the above techniques, you should be able to restore balance to your apple tree and enjoy it for decades to come. 

The Hibiscus Trio

Standard

Perennial hibiscus (Hibiscus moscheutos) left, Chinese hibiscus (Hibiscus rosa-sinensis) middle, rose of sharon (Hibiscus syriacus) right. Photo: http://www.plant-world-seeds, http://www.amazon.ca & http://www.villagenurseries.com

I receive a lot of gardening questions and a surprising number concern hibiscus. Either a lot of people are growing hibiscuses or a lot of people are having trouble with them! 

The problem is, I can’t answer a question about a hibiscus plant without knowing which hibiscus you’re referring to. So, it would help me (and you) to know which hibiscus you are growing. 

Yet, to many gardeners, a hibiscus is a hibiscus, period. How complicated can it be? 

Very complicated, actually.

Three Out of Hundreds

There are actually hundreds of species of Hibiscus found all over the world, including annuals, perennials, shrubs and—yes!—even trees! Some are grown as ornamentals, others for their edible flowers and fruits and even some for their fibres! All, of course, are in the mallow family (Malvaceae) and their flowers look a lot like mallow blooms, but bigger.

However, when most people refer to hibiscuses, they have one of three species in mind, all, initially, with similar flowers: large and disc-shaped with 5 broad petals and a striking central column composed of anthers surrounding an even longer style. All come in various colors and can be simple, semi-double or double and most have flowers that last but a day, sometimes two, but, of course, all bloom repeatedly.

Let’s look at all three.

Perennial Hibiscus, Hardy Hibiscus, Rose Mallow or Swamp Rose Mallow (H. moscheutos)

Perennial hibiscus (Hibiscus moscheutos ‘Pink Elephant’). Photo: http://www.perennialresource.com

This hibiscus is a herbaceous perennial and is hardy from USDA hardiness zones 5 to 9, even zone 4 with a little winter protection. It can be very tall (up to 15 feet/4.5 m!), but modern cultivars are usually in the 3 to 7-foot range (1 to 2 m). Its stems are quite woody for a perennial and need to be cut back in spring.

Most modern cultivars of perennial hibiscus (Hibiscus moscheutos) have overlapping petals. Photo: amazon.com

Perennial hibiscus starts its growth cycle very late in the spring, often a full month after other perennials have started to sprout, but then grows quickly. It produces huge flower buds that open into giant flowers, often said to be dinner-plate size and that’s scarcely an exaggeration: some are 9 inches (25 cm) in diameter, by far the largest flower of any perennial. They come in a wide range of shades, from white to pink, red and purple, often with a red eye. 

It can be a very late and brief bloomer colder climates, but has long blooming period, from July to September, in milder ones.

The leaves of perennial hibiscus (Hibiscus moscheutos)are quite variable in shape, but usually mid-green. Photo: http://www.monticello.org

Its leaves are quite variable and can be broadly ovate to lanceolate, even heart-shaped, and sometimes bear 3 to 5 shallow lobes. Curiously, the shape can vary on the same plant. They are usually medium green (some cultivars have bronze foliage).

It’s the only one of the three commonly grown from seed.

Rose of Sharon, Shrub Althea and Shrubby Hibiscus (H. syriacus)

Rose of Sharon (Hibiscus syriacus) is a temperate-climate shrub. Photo: amazon.ca

This hibiscus is a shrub adapted to temperate climates: USDA hardiness zones 5 to 8, even 4 with winter protection. It reaches 7–13 feet (2–4 m) in height and branches abundantly. 

Rose of Sharon (Hibiscus syriacus) offers an interesting color range. Photo: spaldingbulb.co.uk

It has the smallest flowers of the three, but still, they are about 1½ to 4 inches (4 to 10 cm) in diameter and very showy. They come in white, pink, red and “blue” (blue-violet), often with a red or purple eye. It also has the smallest leaves of the three, with three distinct lobes.

Chinese Hibiscus, Tropical Hibiscus or China Rose (H. rosa-sinensis)

Chinese hibiscus (Hibiscus rosa-sinensis) is, outdoors, a large tropical shrub. Photo: http://www.kalliergeia.com

Of unknown origin, this plant is a tropical shrub and is only grown outdoors year-round in tropical or subtropical climates (USDA hardiness zones 9 to 11). That said, it is also widely available in temperate climates as a houseplant and patio plant. 

The Chinese hibiscus (Hibiscus rosa-sinensis) comes in a remarkable range of colors. Photo: rsrevathi.blogspot.com

Chinese hibiscus can be anything from 1 to 12 feet in height (30 cm to 4 m) and has woody branches. The flowers, usually about 3 to 8 inches (7.5 to 20 cm) in diameter, come in a wide range of colors: red, pink, white, yellow, peach, orange or purple.

The Chinese hibiscus (Hibiscus rosa-sinensis) is often sold as a houseplant or patio plant. Photo: http://www.lowes.com

It can flower all year long, although generally mostly heavily in spring and summer when grown as a container plant or houseplant. Leaves are dark green (sometimes variegated) and ovate with toothed edges.

Obviously, since it’s a tropical plant, it tolerates no frost.

Synopsis

So, three hibiscuses, all with far too many common names: one a perennial (H. moscheutos), one a temperate shrub (H. syriacus) and one a tropical shrub used as a houseplant or patio plant (H. rosa-sinensis). Give all of them full sun, never let them dry out completely, fertilize occasionally and apply whatever special conditions they need to get them through the winter. But you do need to know which is which if you’re going to succeed with them … or if you want to ask questions about them. 

Controlling Powdery Mildew on Squash and Cucumbers

Standard

Powdery mildew affects older leaves first. Photo: u.osu.edu

In many areas, it’s been a dry summer … just the condition powdery mildew (PM) likes … and cucurbits (cucumbers, melons, and squash, including pumpkins, zucchinis and patty pans) get more than their fair share of the disease, especially squash.

PM is pretty much the only plant disease that actually develops best on dry leaves. The perfect conditions? Humid air, no rain and moderate temperatures: 68–80°F (20–26°C).

Powdery mildew first starts to develop as whitish patches under leaves… but few of us think to check! Photo: u.osu.edu

On most plants, PM tends to be late season disease, rarely noted much before August. On cucurbits, powdery mildew first shows up when an apparent powdery residue covers the older leaves. It actually first shows up on the underside of the leaf, generally sight unseen, before migrating to the top side. Affected leaves then die back and that can sometimes lead to sun scald on the fruit underneath. Often it spreads to younger leaves and sometimes kills back the stems.

It’s worth noting first that PM is not one disease, it’s many diseases. In cucurbits alone, there are at least 2 different PM species in 2 different genera (Erysiphe cichoracearum and Podosphaera xanthii, formerly Sphaerotheca fuliginea) and each has several strains, all strictly adapted to cucurbits. You therefore needn’t worry that it will spread from your infected cucurbits to your other garden plants.

Many squashes have silvery markings on their leaves. These are visible from the beginning of the season are not a sign of disease. Photo: plantvillage.psu.edu

Many modern cucumber and melon varieties are naturally resistant to powdery mildew, although some heritage varieties are highly susceptible to it. However, there are fewer such choices in squashes. Even so, if you’ve had a problem one year, ideally, you’d look for a PM resistant variety for the following year’s harvest.

What to Do

Powdery mildew often appears so late in the season that often it doesn’t much affect the crop. With summer squash, for example, you’ve often pretty much finished harvesting before it shows up (or else you have so many zucchinis you really don’t care if you lose a few). Therefore, sometimes there is no need to react, except to remove any leaves that are so covered with mildew they turn yellow and are no longer carrying out photosynthesis.

Also, winter squash fruits often continue to mature in spite of the disease affecting their leaves. You’ll often see fields of pumpkins with damaged or dying leaves, for example, yet the fruits themselves will be fine.

With powdery mildew, the important thing is to slow down its progress. You can do so by spraying with any number of fungicides available at your local garden center (horticultural oil, neem, etc.). Make sure the fungicide is approved for edible plants. And always read the label before you apply: many fungicides, for example, should not be applied in extremely hot weather (temperatures above 85° F/32° C).

Home remedies like baking soda (5 mL/1 tsp. in 1 quart/1 liter of water, plus a few drops of insecticidal soap) or milk (1 part to 9 parts water), can also be quite effective.

Prevention Worth a Pound of Cure

With powdery mildew, it’s easiest to put your effort into prevention rather than treatment.

  1. Destroy infected plants at the end of the harvest.
  2. Practice crop rotation, not planting any cucurbits in the same spot for at least 4 years.
  3. Plant only resistant varieties. (This is such a simple solution that I’m always amazed so few gardeners look into it.) Good seed companies will mention which varieties are mildew resistant. If yours doesn’t, here are some choices: Squashes Resistant to Powdery Mildew.
  4. Plant cucurbits in full sun and space them appropriately (don’t overcrowd) to ensure good air circulation.
  5. Avoid excess fertilizer, especially ones rich in nitrogen.
  6. Water regularly in case of drought, as drought-stressed plants are more susceptible to PM, and, for once, don’t worry about moistening the leaves when you water, as PM develops best on dry leaves.

Seeing cucurbit leaves turn powdery white can be quite a shock the first time you see it, but since it doesn’t always affect the harvest to any degree, most gardeners learn to take it in stride. Personally, just choosing resistant varieties and carrying out simple crop rotation have given me all the mildew protection I need. That may be enough for you as well!

Article adapted from one published on September 1, 2016.

Has the Gypsy Moth Met Its Match?

Standard

Gypsy moth caterpillars often appear in their thousands! Photo: http://www.dufferincounty.ca

When I was a boy (back in the 1960s and early ’70s), I can recall the near paranoia about the gypsy moth in my area (Toronto, Canada).

Distribution of gypsy moths. Green indicates its natural distribution, blue, the areas where it was introduced. Ill.: http://www.forestpests.org

The pest was, at that time, near the Canadian border, and we were warned it would soon invade and destroy our forests. We were told to check our cars and camping equipment when we came back from New England, where it was well established, and certainly never to transport firewood across the border.

Forest defoliated by gypsy moth caterpillars. Photo: University of Georgia

Well, it did cross the border and then some, and continues to spread, but the forests weren’t destroyed. Yes, it causes very visible destruction, with entire trees defoliated and, in years of serious outbreaks, wide patches of forest barren of leaves in late July can be startling, but most trees recover and soon produce new leaves. Where it attacks repeatedly, year after year, it will undoubtedly affect the mix of species in the forest (its preferred host is the oak, although it will easily move to over 500 other tree species,  including alder, apple, aspen, beech, birch, black gum, cherry, hawthorn, hemlock, hornbeam, larch, linden, maple, pine, sassafras and spruce), but it has certainly not been destroying entire forests as I had imagined.

And now, a new gypsy moth parasite may be bringing its numbers down to—dare I say?—sustainable levels.

My Experiences

I’ve only personally encountered gypsy moths twice. 

Female gypsy moth laying eggs. Photo: fyi.extension.wisc.edu

Once was about 20 years ago, when I found a female moth laying a mass of eggs at the base of my crabapple tree. She was certainly easy to see, being so white against on the dark gray bark. Mother and progeny were quickly scraped off and I’ve never seen hide nor hair of a gypsy moth in my garden since.

Gypsy moth caterpillars dying from fungus infection. Photo: Simisky, ag.umass.edu

The other was in Rosemère, Québec, in July 2019, when I was visiting a private garden. The owner took me over to a shady corner to show me a strange phenomenon; a cluster of what must have been thirty caterpillars on a tree trunk, all facing down. They were mostly immobile, although some nodded slightly. They didn’t react to our presence, even when we touched them. They were dying, attacked by a fatal fungus, Entophaga maimaiga (fatal to gypsy moths, that is). 

That’s what this article is about, a “new” fungus that may will put the gypsy moth in its place. But first, a bit of history and general information.

Back Story

Male and female gypsy moths (including males that died after mating, congregating on a tree trunk. Photo: Patrick Hodge, MNR

The gypsy moth (Lymantria dispar) is native to Eurasia and northern Africa. There are several different subspecies, each with different host preferences. The one brought to eastern North America is the European gypsy moth (Lymantria dispar dispar). It’s the one with the oak fetish … and also one where the female insect doesn’t fly. But more on that later.

The European gypsy moth was accidentally introduced to the New World by French entomologist Étienne Léopold Trouvelot (1827–1895). He brought it from Europe in 1869 with the idea of crossing it with silkworms (Bombyx mori) in order to develop a silkworm industry in New England. However, the moths soon escaped from his residence in Medford, Massachusetts. 

At first, they had little impact, but in 1889, therefore 20 years later, a major outbreak occurred, with entire forests being defoliated and caterpillars covering houses and sidewalks.

Visual showing the spread of the gypsy moth in the United States from 1910 to 2007. Ill.: US Forest Service

The gypsy moth then slowly spread across New England and is now present throughout most of the Eastern United States and southeastern Canada. It occasionally pops up in Western North America too, but such local infestations are quickly quashed by local authorities.

Air-Borne Caterpillars

One thing that intrigued me as a child was that I was told the female moth of the European subspecies didn’t fly, but the males did. I just couldn’t figure it out: if female gypsy moths don’t fly and they laid the eggs of the next generation, how could gypsy moths possibly spread? Wouldn’t the females just live on the tree where they hatched or, at most, a neighboring tree, and lay their eggs there? That wouldn’t get them very far!

Young caterpillar hanging by a thread. Photo: Chris Seto, http://www.cbc.ca

It turns out that, after hatching, some of the larvae, still tiny, move high up into trees, then hang by threads from branches. From there, they can be blown considerable distances, possibly using the thread as a parachute. Apparently, that’s how they crossed Lake Michigan to reach Wisconsin, a distance of at least 50 miles (80 km)! 

Without intervention, gypsy moths spread on average some 13 miles (21 km) per year. Pretty good for an insect with stubby legs that can’t fly!

Gypsy Moth Life Cycle

There is only one generation per year.

Male moths have an impressive pair of antennae. Photo: gov.bc.ca

In North America and Asia, adult gypsy moths appear in late July or August. They’re rather nondescript moths, hard to distinguish from other species. The brownish males with feathery antennae fly mostly at night and mate with several females. The latter are white with black markings, have thin antennae and, despite the fact they have wings, do not fly.

They give off a powerful pheromone that attracts males from afar. Adults neither feed nor drink and die after about a week, but not before the female has laid about 100 to 1,000 eggs, usually on the lower part of tree trunks or on shrubs, rocks, stumps, vehicles, outdoor furniture, sides of buildings or firewood. 

Females with egg masses. Photo: http://www.oakville.ca

If seen, the egg masses have a spongy appearance, covered with tan or buff hairs, and can be scraped off and disposed of. Wear gloves, as the hairs are irritating.

Eggs overwinter where they are laid. They can be killed by severe cold: 16˚F/-9˚C is sufficient if maintained over a long period, but -9˚F/-23˚C can kill them after only a few hours. Still, they can survive under snow and other protected spots in colder climates. 

Dormant oil spray can be used to destroy the eggs.

Young caterpillars are tiny. Photo: onnurserycrops.com

Eggs hatch in the spring, about the time the first leaves appear on trees. The larvae look much like the caterpillars of other forest caterpillars such as tent caterpillars (Malacosoma spp.): blackish and hairy. Both types are mostly noticed not only because of the extreme damage they cause (serious defoliation), because they appear in such large numbers, something especially noticeable as they grow in size, from only 1/8 inch (3 mm) in length at first to up to about 2 1/2 inches (60 mm) just before pupation. As they reach maturity, you can more easily tell gypsy moth caterpillars from other species by the double rows of five raised blue dots near the head followed by six similar red dots. 

As they get older, you can count the dots: 5 blue near the head, then 6 red. Photo: WSDA

Caterpillars can be squashed or dropped into soapy water. The hairs are irritating to the skin and can even cause allergic reactions, so wear gloves. Or spray them with Btk (Bacillus thuringiensis kurstaki), a widely available biological insecticide. Surrounding the trunk of an infested tree with a sticky product like Tanglefoot can also trap them. 

Notice the frass accumulating (some of it whitened by fungus) underneath the caterpillars. Photo: Benoît St-Amant

The caterpillars also produce frass (caterpillar poop), often in huge quantities, covering decks and garden furniture. You can even hear it hitting the ground, like little drops of rain. Besides being annoying and disgusting, it can be quite slippery after a rain and requires a lot of cleanup. But, to give frass its due, it does feed the forest in minerals.

Two pupae. Photo: fyi.extension.wisc.edu

By mid-June to early July, the caterpillars leave their tree and look for a hiding place—between ridges of bark, under loose bark, under branches or leaves, in fissures in rocks, on the ground, etc.—and turn into pupae. This is also when they most often hitch rides on vehicles, camping furniture and firewood. The pupae are brown and shell-like, somewhat hairy. Again, if you find any pupae, they can be squashed or dropped into soapy water.

The adults emerge after 14 to 17 days … and a new cycle begins.

Predators and parasites

A braconid wasp attacking a gypsy-moth caterpillar. Photo: USDA, Wikimedia Commons

Since the gypsy moth was first accidentally released in North America, all sorts of parasites and predators have been imported from Eurasia and released in order to control it. Many failed to adapt and disappeared, but there are now several parasitic flies and wasps that are well established over the gypsy moth range and are reducing its numbers. And a few native parasitic wasps also help. Also, several viral diseases have become established and can cause significant mortality. One, Lymantria dispar multicapsid nuclear polyhedrosis virus (LdMNPV), often shortened to NPV, is also used as an insecticide under the name Gypchek

Birds, too, eat gypsy moth adults, larvae and eggs. In Eurasia, they’re apparently a major source of control, but North American birds have been slow to adapt, possibly put off by the caterpillars’ irritating hairs, and are not considered effective controls. The very common white-footed mouse (Peromyscus leucopus) has proved a very good control, though, at least where moth populations are sparse, and shrews too can be effective predators.

New Kid on the Block

Spores of gypsy moth fungus (Entophaga maimaiga). Photo: US Forest Service, Wikimedia Commons

However, a new pathogen, specific to gypsy moths (thus not harmful to other moth species), seems to be outcompeting the others: gypsy moth fungus (Entophaga maimaiga). (Maimaga is the Japanese common name for the gypsy moth.)

Although first introduced from Japan to North America near Boston in 1910 and 1911 during an early attempt to control the gypsy moth invasion, it apparently never established and the release was considered a failure. Further releases were made in 1985 and 1986 in New York State and Virginia. Again, the releases were considered unsuccessful. 

However, in 1989, the fungus re-emerged in New England. Some entomologists believe the new cases derive from the original release (1910/1911), although no one knows where the fungus spent the intervening 75-odd years. It had apparently been slowly adapting to North American conditions all that time. 

Gypsy moth fungus has since been spreading rapidly throughout gypsy moth territory. It is so effective that is relegating other disease and insect pathogens to very secondary roles. 

Gypsy moth fungus will certainly never eliminate the gypsy moth entirely, but some entomologists feel it may well be the pathogen that will finally keep the gypsy moth in check. Certainly, in areas where this fungus has been found, gypsy moth populations quickly crash and rarely reach more than moderate levels thereafter. 

The Fungus Life Cycle

Wind-borne spores of gypsy moth fungus land on the caterpillars and infect them by penetrating their skin. 

Early in the season, after overwintering on the ground, spores are carried by wind to young caterpillars up in the canopy of the tree. The tiny caterpillars die mostly sight unseen, clinging to leaves. 

Caterpillars killed by gypsy moth fungus. Photo: portal.ct.gov

From these small cadavers, the fungus soon produces spores that are carried to larger caterpillars. The latter then gather in groups on tree trunks, always head down, front legs free, arching somewhat outwards. This mass display makes the fungus infestation much more visible. The caterpillars die, turn rubbery, then shrivel. Eventually, they become covered with fungal growth, then drop to the ground and decompose, but the spores released can live in the ground for up to 12 years, assuring long-term control.

If you see a cluster of dark hairy caterpillars on a trunk, possibly nodding slightly—and it’s a more common occurrence every year!—, you’re seeing the start of the demise of the scourge of the northeastern forest, the gypsy moth, soon to be relegated to the status of—everyone hopes!—a rather minor problem!

Further Reading

https://phys.org/news/2016-04-pathogen-gypsy-moth-populations.html
https://en.wikipedia.org/wiki/Lymantria_dispar_dispar

Fun With Flowers: Turn Blooms Rainbow Colors

Standard

Dying flower is a fun and easy experiment. Photo: activity-box.com

Here’s a simple summer rainy day project for bored children. Teach them how to dye flowers! 

Then add a bit of a botany lesson at the end.

Gather the Materials

All you need are white or pale-colored flowers fresh from the flower garden, a few tall glasses, water, scissors, a stirring spoon and some food coloring (food coloring is nontoxic to plants).

Among the flowers you could choose from are daisies, cosmos, tulips, chrysanthemums, lilies and roses, but really, almost any flower will work.

They should be white or a pale color, though; dyes won’t show up as well on darker flowers. And avoid fading flowers: fresh flowers just opening are best.

White flowers placed in colored water. Photo: http://www.momtastic.com

Step by Step

  1. Harvest fresh flowers from the garden. 
  2. Strip the flowers of their lower leaves (any that will be underwater). 
  3. Fill the glasses three-quarters full with warm water.
  4. Add about 20 to 30 drops of food color (your choice of color) to the water and stir.
  5. Insert the flower’s stem into the glass, then recut the stem underwater. (Recutting underwater ensures colored water moves into the cut stem, not air bubbles.)
  6. Remove the bit of floating stem.
  7. Repeat with other colors. You can mix food colorings to create your own original hues.
  8. Come back in a few hours to see if there is any difference. Then again yet a few hours later. With some flowers, the full color change can take nearly 24 hours.
White carnations turned pastel shades. They also “drank” a lot of the colored water! Photo: makeitorfixit.com

By the end of the project, you’ll have turned the white flowers to various shades. You can use them to create a lovely bouquet, perhaps a gift for someone’s birthday!

How Does This Work? 

How much you explain to the children will depend on their age … and their scientific bent, but here goes for a rough explanation.

Flowers lose water through transpiration: their open pores allow water to evaporate (disappear into the air). To compensate, they absorb more.

Capillary action moves water up any tube: the narrows the tube is, the higher the water will go. And xylem is really narrow! Ill.: http://www.metalroofing.org.nz

Colored water from the glass will move up the stem through tiny tubes called xylem. It moves up the xylem due to cohesion: water molecules attract each other and move it up the stem, carrying dye to the blooms. This is called capillary action. It’s much like sucking on a straw will pull water from a glass into your mouth, except it’s the evaporation from the flower above that does the pulling. 

The fresh water evaporates from the flower, but the dye doesn’t, leaving the flower color changed.

Will Flowers Also Absorb Dye Through Their Roots?

That’s a question the children might ask you.

This could also be another experiment to try, but it’s more complicated: you’d need potted plants bearing white or pale blooms. Plus, it’s easy for overeager young waterers to drown the plant with repeated doses of colored water. And rotting plants may not be your ultimate goal.

That’s why you might just want to explain the situation to the children rather than demonstrating it.

Here’s what you can say:

Plants won’t absorb food coloring through their roots. Ill.: clipartpanda.com, montage: laidbackgardener.blog

Plants usually absorb water and nutrients through their roots, but roots are also designed to be filters in order to keep out toxins. They act as a defensive barrier and only absorb what plants need in order to grow. That means that little if any coloring (even though it isn’t toxic) will get through and so no color change will occur in the flowers. And all that food coloring would just go to waste!

Edelweiss: the Garden Plant Inspired by a Song!

Standard

Edelweiss (Leontopodium nivale alpinum). Photo: J&Konrad, flickr.com

EDELWEISS
Leontopodium nivale alpinum

Dimensions: 6 to 14 in (10–40 cm) high × 8 to 14 in (20–40 cm) wide
Exposure: ☀️
Soil: well drained, gravelly, slightly moist to somewhat dry, not too rich
Flowering Season: June-July
Multiplication: division, seeds
Uses: flower bed, border, bed, rockery, low wall, container, xerophytic garden, cut flower, dried flower, medicinal plant
Associations: pinks, dwarf grasses, houseleeks, gentians
Hardiness zones: 3–7

There are more than fifty species of Leontopodium (the name means “lion’s paw” because the flower bracts look like claws) distributed throughout the alpine and arctic zones of Eurasia, but only one is commonly cultivated: the alpine edelweiss (L. nivale alpinum, most often sold under its former name, L. alpinum), native to the Alps and other mountains throughout Europe. 

Edelweiss is the German common name and means “noble white”. In Italy, it’s known as “stella alpina”: star of the Alps.

Most of us first heard about the edelweiss in the movie The Sound of Music,. Photo: abcnews.go.com

The plant was popularized by the eponymous song from the musical The Sound of Music, written by Richard Rogers and Oscar Hammerstein II, which means more people know the song than have seen the plant, as it remains relatively rare in gardens … and not all of us have scoured the Alps looking for it. 

Despite the popular belief that the edelweiss is the floral emblem of Austria, that isn’t quite true. That role falls to the alpine gentian: Gentiana alpina. It is, however, the official floral emblem of neighboring Switzerland. But Rogers and Hammerstein were really not mistaken in choosing the plant as the theme of their song about Austrian nationalism, as it features on Austrian coinage and stamps and is the insignia of Austria’s alpine troops.

The real flowers (in the center) are rather insignificant, but the fuzzy white bracts that surround them really do give the impression of a “flower of snow”. Photo: seedcorner.com

The plant forms a tuft of erect, outward-arching stems bearing lance-shaped leaves covered with white hairs, giving the leaves a silver-gray appearance. The inflorescence consists of a cluster of five to six small flower heads made up of tiny florets that are woolly white in bud, but creamy yellow when they open. What catches the eye, however, is the collar of white woolly bracts that surrounds the flower head, usually mistaken for the flower’s petals.

It is an absolutely stunning plant when discovered during a hike in the Alps, but sometimes disappointing in cultivation, as the bracts tend to turn grayish rather than white when soaked with rain and are often stained by particles of soil as well. To keep them clean, cover the soil around the plant with a layer of fine gravel … and while you’re at it, you might want to choose dark gravel, as that will bring out the beautiful silvery gray of the foliage and the sparkling whiteness of the bracts.

As a child, I always had the impression that edelweiss was rare and extremely difficult to grow, perhaps nearly impossible to cultivate outside of the Austrian and Swiss Alps. But in fact, it’s reasonably easy: not rudbeckia or coreopsis easy, but something any serious temperate-climate gardener ought to be able to handle. 

Edelweiss is ideal for rock gardens. Photo: http://www.jparkers.co.uk

Edelweiss prefers full sun or only the very lightest shade and perfectly drained soil. You might want to mix about one third fine gravel into your usual soil to replicate alpine conditions. It grows well in alkaline soils, but adapts to moderately acid ones as well. It will tolerate drought once established, although first-year plants are still quite fragile.

The plant is often said to be “short-lived,” but this is especially the case when it’s grown in a regular flower bed in rich, fairly moist soil. (And yes, that can be done.) But if you try to recreate its natural environment, that is, alpine conditions, edelweiss can live for many years. It especially likes cool summers, obviously not something every gardener can provide. It may self-sow to a certain degree when it likes your garden, but not to the point of becoming invasive.

Edelweiss fairly easy to grow from seed (and no, you don’t need to give it a cold treatment), but you can also multiply it by division.

Where to find it? Your local garden center may not carry edelweiss (mine doesn’t), but it’s common enough in specialized alpine nurseries and many seed companies offer seeds. You can even find seeds on eBay and Amazon.

Varieties

Leontopodium nivale alpinum ‘Everest’. Photo: Fleuroselect

Leontopodium nivale alpinum ‘Everest’: dwarf variety. Sometimes blooms the first year from seed. Fleuroselect winner. 7–8cm x 8–10 cm. Zones 3–7.

Leontopodium alpinum ‘Mignon’: more compact than the species. 10–20cm x 20–30 cm. Zonea 3–7.

No Pesticides in Hot Weather

Standard

Ill.: planetpermaculture.wordpress.com, www.pngguru.com & clipart.me, montage: laidbackgardener.blog

Most gardeners clearly understand that applying pesticides on a rainy or windy day is not going to be very effective, but heat also be a factor to consider. On those really hot days, some pesticides, and that includes organic ones, can damage the plant at least as much as the pest. 

Always Read the Label

That you ought to read a pesticide label before applying it should be obvious, but gardeners who regularly use the same pesticide often figure they know it well and skip this step. When the weather is hot, though, get out your reading glasses (or a magnifying glass: sometimes that small print is really small!) and give the label a thorough read over. If the product should not be applied in hot weather, it will say so!

You’ll find that even “safe” insecticides, like insecticidal soap, neem and horticultural oil, can kill or damage plants when applied in hot weather. Most emulsifiable pesticides warn not to apply them at temperatures above 90˚F (32˚C). 

Dusts and powders are less likely to cause damage to plants at high temperatures than oils and soaps, but still, read the label!

Damage is most likely on young growth and flowers, less so on mature leaves and stems. and may include spotting, dead zones, stunted growth, deformed fruit or even the death of seedlings.

Of course, insects and diseases are not going to wait until temperatures drop. Fortunately, you can apply many of these temperature sensitive products early in the morning or in the evening, when temperatures are likely cooler. Or maybe wait a few days if the weather is expected to cool down

Vapor Drift

Damage to the plant being treated is only one factor to consider. Many pesticide products are volatile and will be carried much further in hot weather then at normal temperatures, thus reaching non-target plants, beneficial insects or even fish in a nearby pond. Often the cut-off temperature for these products is 85˚F (30˚C). Usually, too, the label of such products will warn not to apply them at all during hot weather, even during cooler hours, as they can vaporize hours after application.

Herbicides Too

The information above applies to not only insecticides, but also herbicides. 

Herbicide damage to tree leaves. Photo: nfs.unl.edu

One man recently wrote that the lower leaves of his trees were twisted and contorted with brown margins and was convinced some disease or insect was involved, but I thought it odd that only the lower leaves were damaged. I asked if he had sprayed a lawn herbicide during a recent heat wave. He said no, then recalled serving lemonade to a sweaty lawn care company employee obviously suffering on a very hot day. It turned out he had sprayed a herbicide on the grass below and it had drifted up to the foliage of the trees. 

These companies are not supposed to apply such products during hot or windy weather, but … they do. If they show up at your place during a heat wave, send them packing!

Home Remedies

There are no labels you can check for home remedies and indeed, many of them are fairly innocuous, but even so, they could still cause damage. I’d suggest not applying any home remedy at temperatures about 85˚F (30˚C), just to be certain.

Heat and pesticides: they just don’t mix!

Garden Myth: Exposing Tomato Fruits to Sun Helps Maturation

Standard

Even tomatoes completely hidden by foliage ripen. Photo: http://www.denverpost.com

At the end of the summer, my father always stripped the upper leaves off his tomato plants so the fruits would mature more quickly. After all, he reasoned, exposing fruits to the sun makes them ripen, so getting rid of the leaves shading his tomatoes ought to ensure an earlier harvest and less risk of them being destroyed by frost.

And he wasn’t alone in this belief: it was common practice 60 years ago.

I thought this was one garden myth that had mostly died out, as I wasn’t seeing it much anymore, but, judging from the questions about the technique I’ve been receiving lately, it seems to be on its way back in. Maybe this article can help nip that in the bud.

What Makes Tomatoes Ripen

Tomatoes ripen when they are ready to mature, period. You can’t do much about it. Some varieties mature faster than others: it’s built into their genes. More sun (on the leaves) also gives faster maturation; tomato plants in partial shade produce less and their fruits are slower to mature. The weather is another factor, of course. Tomatoes do ripen most quickly at warm but not hot temperatures, but what can you do about that? And yes, keeping them evenly watered helps too. Drought-stressed tomatoes are a bit slower to mature. Adding extra fertilizer is likewise a waste of time. Unless the plant is suffering from a mineral deficiency, it won’t speed up ripening per se.

So, besides providing the best possible conditions for your tomatoes, there’s not much you can do to speed up maturation.

Unless leaf pruning can help?

A Simple Test

Tomatoes ripen just as readily in the darkness of a paper bag as in the sun. Photo: anoregoncottage.com

It’s easy enough to prove that exposure to sunlight doesn’t help tomatoes ripen. Just harvest two tomatoes that still green, but near maturity. Place one in a brown paper bag, perhaps putting it in the pantry to be sure it’s really in the dark, and leave the other exposed, setting it on a sunny windowsill. You’ll see that both mature at the same time and yet the one kept in the paper bag received absolutely no sunlight.

So, it’s pretty clear no sun actually has to touch the fruit for it to mature.

Sunscald and Insipid Taste

The worst part of this myth is that not only stripping tomato plants of their leaves doesn’t help the fruit mature, it can be downright harmful.

Sunscald on a ripening tomato. Photo: MAPAQ

Fruits that were completely shaded by leaves, then suddenly exposed to full sun, may actually suffer sunscald (the plant equivalent of sunburn). They’ll still be edible, but won’t be as presentable. And you have to cut away the damaged part, so they give you less fruit to eat.

Also, foliage, because it captures the sun’s energy and converts it into sugar, gives tomatoes their sweet taste: if you strip off the plant’s leaves, the tomatoes that are forming won’t be quite as tasty! And the plants won’t be as prolific. The more leaves a tomato plant has, the more fruits it can produce.

Of course, you can remove yellow, brown or diseased leaves (that’s another situation entirely), but leave green leaves intact if you want the tastiest, most perfect tomatoes in town!

Article adapted from one published on August 21, 2015.

When a Baby Bird Falls From the Nest

Standard

Photo: Mandy Dickinson, nwf.org

This is far from an uncommon occurrence. If your garden has plenty of trees that birds could nest in, it’s something you’re bound to run into. Sometimes, it happens several times a summer.

What should you do? Well, first, assess the situation. Starting with … what does the young bird look like?

Fledglings

This is a fledgling. It is fully feathered and probably “trying out its wings” when you find it. Photo: flickr.com

If it’s a fledgling, that is a young bird fully feathered, not yet flying, but able to hop, you probably don’t need to do anything. It was probably learning to fly and ended up on the ground. The parents are likely nearby and in fact, may be making quite a ruckus. While their cries may seem like a distress call, they’re actually encouraging the fledging to try again. 

If you leave it alone, the parents will likely come and feed it. In many species, fledgings usually do spend a few days on the ground or in low branches, working things out. This is just normal fledgling behavior. You might want to keep an eye on it for an hour or so, just to make sure the parents are caring for it. Otherwise, all you really need to do is to keep your cat indoors until it finally does take off.

Unfortunately, about 80% of the baby birds placed in rehabilitation centers are fledgings that were kidnapped by people thinking they were helping out, but they weren’t. Fledgings shouldn’t be taken from the wild. They were doing fine on their own!

You can put the little guy onto a low branch if you want: it will be a little safer than on the ground. But don’t put it back in its nest, even if you can see it: it has passed that stage and will only leave immediately. The nest is no longer its home.

But what if it is injured, with say a wing that sticks out instead of folding up, or there are signs of blood? Or it’s been attacked by a cat? (That may leave wounds that aren’t obvious, but could become infected.) Or maybe the baby is clearly weak? Then you should consider calling your local wildlife department to learn what licensed wildlife rehabilitation programs are available.

Nestlings

This is a nestling, with only down and no real feathers. It’s too young to be on its own. Photo: http://www.birdhousebuilder.com

What, though, if it’s a nestling, scrawny, downy and featherless, far too young to be on its own? It was probably blown from the nest or accidentally pushed out. Such a bird will likely die if you don’t intervene. 

Try to locate the nest, probably in the tree just above the baby. If you can and it’s of easy access (don’t risk your own life trying to save a baby bird!), put the baby back in the nest. Be forewarned that the parents may try to dive bomb you: they’re protecting their nest and don’t understand you’re trying to help.

Yes, you can pick pick the nestling up in your hand. The belief that mother birds will be able to smell that a human has handled a nestling and will then reject it is just an old wives’ tale.

If there’s more than one nestling on the ground, it’s likely the whole nest has blown down. If you can find it and it’s intact, try putting it back, fixing it to the branch with twine or wire, and setting the babies inside. If it’s in pieces, prepare a substitute nest, for example a small wicker basket, a kitchen strainer or a plastic bowl with a hole in the bottom (so any rain will drain out), line it with dry grass or cloth, then attach that to the tree. Then put the nestling(s) inside. 

Do this quite quickly, as birds that young are quite fragile.

Now, watch the situation. If no parent bird shows up, call your local wildlife department.

Mobile Babies

A baby pheasant is precocial and active. It doesn’t need your help. Photo: Anna Bilska, flickr.com

What if it’s on the ground and running about, yet still covered in down? Then it’s probably “precocial”, from a species like a grouse, pheasant, duck or plover that nests on the ground. These babies are up and mobile within minutes of hatching, even feeding themselves. So, actually, there may not really be anything wrong, other than your presence that has separated the baby from its parents. So, pull back out of sight and wait to see if the parents aren’t just waiting for you to leave before collecting their baby. Usually, they are and the family will soon move on. Only if there is no sign of the parents after two hours should you consider intervening.

While Waiting for the Wildlife Rehabilitator

Keep the baby bird comfortable in a box while awaiting help. Photo: http://www.change.org

So, mama and papa bird have not shown up and you’ve called the appropriate wildlife rehabilitator? If so, they’re either coming or you’re to take it to them. In that case, put the baby bird in a small box like a shoebox with a cloth or some paper at the bottom and keep it warm, quiet and out of the wind and rain. Do not feed it. (Each species has its preferred diet and can be harmed if you give it the wrong one.) 

What Not to Do

Do not bring the bird into the house thinking you’ll care for it yourself. In most areas, raising a native bird is illegal. In North America, it’s in the Migratory Bird Treaty Act that covers Canada and the US. Even if you did try to raise it, it would not likely survive once released. A specialized rehabilitator, though, would know what to feed it and how to care for it and make sure it learns the basics of survival on its own before releasing it.

Or…

Or just walk away and let Mother Nature take care of the situation. She’s pretty cruel, though. One estimate is that only 30% of baby songbirds survive their first year. Baby birds are an important source of food for a large number of animals and other birds: foxes, hawks, snakes and many more. Some have to be sacrificed for the circle of life to continue: that’s just the way it is!