We ’ve had an implausibly wet summer this year here in Pennsylvania . That combined with our cooler temperatures has created the perfect formula for fungal diseases . Although my tomatoes have yet to recrudesce blight ( knock on wood ! ) , my bee balm is perfectly smothered in powdery mould . unhappily , this fearless perennial is notorious for its susceptibility to this fungal return . And though the mildew is n’t likely to kill my plants , it certainly does make them look hapless by covering the leaves with a overweight white dust . Severe infections can limit photosynthesis , and impede increase and proceeds in vegetable craw .
Powdery mould is the result of several dissimilar coinage of fungal organism that survive on the leaves of certain plants . Lilacs , phlox , Cucumis sativus , grapevine , squash , melons and several other mintage are prone to attack . Yes , it ’s for the most part an artistic return , but there are some things that can be done to facilitate keep powdery mold at bay .
1 . select Varieties WiselyIn the veg garden , be indisputable to choose varieties of squash vine , cucumber and melons with an innate immunity to powdery mildew . Read seed catalog cautiously and look for motley with a proven resistance to the pathogen . you may also see for a “ postmortem ” on the seminal fluid packet itself — that ’s the code cum sellers use to destine a particular variety as powdery mould resistant . On these member of the squash family , powdery mold appears as a white dusting on the leaf that can eventually induce the foliage to turn browned , juiceless up and knock off off .
2 . Water ProperlyPowdery mildew tends to develop when water rests on the leaf control surface , so irrigate near the etymon zona — not overhead — if possible . Watering during the morning is a honorable idea , as well . This allow for the foliation to dry before nightfall . In years like this one , though , Mother Nature is taking care of the lacrimation and her timing has been less than perfect ; it ’s been raining a few nights a hebdomad almost all summer long .
3 . Give Plants SpaceAllow slew of room around susceptible plants to increase the atmosphere circulation . I separate my bee balm every four or five years to keep the flora from fuck off too dense . Be sure to provide plenty of room for vining crop in the veggie garden , as well .
4 . Use Organic FungicidesLike many other fungal infection , powdery mold is best managed preventatively because once the organism take , it ’s hard to control . If I get to to do anything at all , I use a biofungicide base on the active element Bacillus subtilis . B subtilis is a bacterium that attacks many fungous organisms , include powdery mildews , rusts , anthracnose , blights , brownish bunk and several others . It ’s apply as a foliar spray and is certified by the Organic Materials Review Institute . Ideally , you should begin to use it early on in the time of year harmonise to label instruction and make regular diligence to keep the fungus from taking hold . Although several name brand exist , the one I see most often at my local nursery is Serenade .
5 . Remove Diseased PlantsSomeday I will dig out all the susceptible bee - balm assortment at my house and replace them with mildew - resistant variety . Some good options include Marshall ’s Delight ( a medium pinko ) , Claire Grace ( lavender ) , Prairie Night ( purple ) , Aquarius ( pale garden pink ) and Stone ’s stroke Pink .
Do more to serve combat disease in your garden :
