Powdery mildew attacks various squash species in mid to late summer. Photo: gardenerd.comldew
Powdery mildew (PM), in which a white powdery growth appears on leaves in mid to late summer, causing distortion, dieback and a serious decline in productivity, is the most common disease of squashes and other cucurbits all over the world. There are actually many varieties of this disease, of which Podosphaera fuliginea (formerly Podosphaera xanthii) and Erysiphe cichoracearum are the two most common.
There are various ways of treating it (see Powdery Mildew on Squash and Cukes for some ideas), but one of the easiest is choosing squash varieties that are naturally resistant to PM.
Resistant varieties are not necessarily immune to PM, but are less affected, often showing no or milder symptoms or the symptoms show up later, after the crop is harvested. Ideally, then, if powdery mildew has been a problem in the past, the wise gardener would choose resistant varieties in the following years.
A List of Disease-Resistant Squash
The varieties below are considered powdery mildew resistant. There are others, often identified by the letters PM or PMR after the cultivar name (i.e. ‘Butterscotch’ PMR) in better seed catalogs.
Look for resistant varieties in seed catalogs, both paper and online.
Summer Squash
Zucchini
‘Amatista’
‘Ambassador’
‘Astia’
‘Black Coral’
‘Cash Machine’
‘Citlali’
‘Cuarzo’
‘Dario’
‘Desert’
‘Dunja’
‘Elegance’
‘Emerald Delight’
‘Emerald Desire’
‘Endeavor’
‘Envy’
‘Equinox’
‘Esteem’
‘Everglade’
‘Felix’
‘General Patton’
‘Golden Glory’
‘Goldy’
‘Green Machine’
‘Hurakan’
‘Jacobo’
‘Judgment III’
Zucchini (cont.)
‘Justice II
‘Limon’
‘Linda’
‘Lynx’
‘Midnight Lightning’
‘Mutabile’
‘Obsidian’
‘Pascola’
‘Paycheck’
‘Payload’
‘Payroll’
‘Prestige’
‘Preference’
‘Respect’
‘Reward’
‘Sebring’
‘Sebring Premium’
‘Seduction’
‘Spineless Beauty’
‘Spineless’ King’
‘Spineless Perfection’
‘Spineless Supreme’
‘Yellowfin’
‘Wildcat’
‘Ziti’
‘#8517’
Crookneck
‘Delta’
‘Fancycrook’
‘Gentry’
‘Gold Star’
‘Prelude’
‘Prelude II’
‘Sunglo’
Straightneck
‘Blonde Beauty’
‘Cheetah’
‘Conqueror III’
‘Dalsey’
‘Multipik’
‘Organic Success’
‘Patriot II’
‘Success’
‘Sunray’
Winter Squash
Butternut
‘Betternut’
‘Betternut 401’
‘Betternut 900’
‘BonBon’
‘Bugle’
‘Butterscotch’
‘Chieftan’
‘Hamilton’
‘Honeynut’
‘Indian Brave’
‘Jacqueline’
‘JWS 6823’
‘Metro’
‘RB 310’
‘Waldo’
Acorn Squash
‘Autumn Delight’
‘Celebration’
‘Harlequin’
‘Honey Bear’
‘Mardi Gras’
‘Royal Ace’
‘Starry Night’
‘Sugar Bush’
‘Sweet Lightning’
‘Sweet Reba’
‘Table Star’ ‘Table Treat’
‘Taybelle’
‘Tiptop’
Delicata
‘Bush Delicata’
Spaghetti Squash
‘Sugaretti’
Pumpkin
‘18 Karat Gold’
‘Aladdin’
‘Apollo’
‘Ares’
‘Bellatrix’
‘Big Doris’
‘Bisbee Gold’
‘Blanco
‘Blue Doll
‘Bumpkin’
‘Cannonball’
‘Captain Jack’
‘Carrie’
‘Casperita’
‘Charisma’
‘Conestoga Giant’
‘Cronus’
‘Darling’
‘Eagle City Gold’
‘Early Abundance’
‘Early Giant’
‘Early King’
‘Field Trip’
‘Gladiator’
‘Gold Dust’
‘Golden Condor’
‘Gooligan’
‘Grizzly Bear’
‘Hannibal’
‘Harvest Princess’
‘Hercules’
‘Hermes’
‘Hobbit’
‘Hooligan’
‘Indian Doll’
‘Iron Man’
‘Jason’
‘Jill-Be-Little’
‘Lil’ Ironsides’
‘King Midas’
‘Kratos’
Pumpkin (cont.)
‘Little Giant’
‘Magic Lantern’
‘Magic Wand’
‘Magician’
‘Mellow Yellow’
‘Merlin’
‘Midnight’
‘Miniwarts’
‘Mischief’
‘Mystic Plus’
‘Naked Bear’
‘Oktoberfest’
‘OneTooMany’
‘Orange Rave’
‘Orange Sunrise’
‘Orangita’
‘Porcelain Doll’
‘Porcelain Princess’
‘Prankster’
‘Pure Gold’
‘Pumpkin Rhea’
‘RockaFellow’
‘Scarecrow’
‘Secretariat’
‘Silver Moon’
‘Snowball’
‘Spark’
‘Spartan’
‘Specter’
‘Sunlight’
‘SuperHerc’
‘Sweet Lightning’
‘Touch of Autumn’
‘Warty Gnome’
‘Warty Goblin’
‘WeeeeOne’
‘Zeus’
Kabocha
‘Winter Sweet’
recipe for homemade pm drench please?? And btw what about patio squash? And resistence there?
It would be really useful to indicate seeds companies that carry these varieties. Most are not common names. For example, the zucchini #8517, rated very high in 2008 Cornell University field experiments, is impossible for a small time gardener to find and purchase. The source for this experiment was Outstanding Seeds, a commercial farm supplier. Amatista variety seems only to be available from Syngenta, another commercial supplier. I’ll keep looking, but if you have any sources please mention them.
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Those are such extensive lists that there does not seem to be much that is not on them. All that I grow is there, which could be why powdery milder is not much of a problem. We get it, but it does not do much damage.