Sunday, December 23, 2012

Green house pest management

Green house pest management can be an overwhelming problem; especially in an aquaponic system.   But these fungi are not limited to soil less gardens or greenhouses.

I'd like to thank Forestry Images for thier wonderfully helpful site.
With great photos to help identify various problems,  microscopic slides and petri dish samples they have made identification much simpler.

Pythium diseases (Pythium spp. ) on flue-cured tobacco (Nicotiana tabacum (flue-cured type)) - 1233227 Pythium diseases
brown spot (Alternaria alternata ) on flue-cured tobacco (Nicotiana tabacum (flue-cured type)) - 1402024 brown spot
Phytophthora blight (Phytophthora nicotianae ) on burley tobacco (Nicotiana tabacum (burley type)) - 1440052 Phytophthora blight Fusarium wilt (Fusarium oxysporum f.sp. nicotianae) on flue-cured tobacco (Nicotiana tabacum (flue-cured type)) - 1402044 Fusarium wilt
blue mold (Peronospora tabacina ) on burley tobacco (Nicotiana tabacum (burley type)) - 1440019 blue mold   powdery mildew (Podosphaera xanthii ) on squashes (general) (Cucurbita pepo ) - 1573677 powdery mildew leaf scorch (Diplocarpon earlianum ) on strawberry (Fragaria x ananassa ) - 5473250 leaf scorch sour rot (Geotrichum candidum ) on melon (Cucumis melo ) - 1575010 sour rot
white ear rot and seedling blight of maize (Stenocarpella maydis ) on corn (Zea mays ) - 5405277 white ear rot and seedling blight of maize bitter rot and anthracnose (Colletotrichum gloeosporioides ) on apple (Malus domestica ) - 5407832 bitter rot and anthracnose

Jon Parr and Vlad are some of the best contributors to the aquaponic  forums.
Here's a little advice they have pasted on that I appreciate.

Link to discussion

GH (Green House) pest management has three strategies, and which is best is really open for debate.
1- intentionally low pest security, meaning wide open large screens for honey bees, pests, and pest predators. This works pretty good for lazy folks like myself, especially if you are planting beneficial plants to attract the predators. No fuss about pollination, and no big concern about sterilizing everything.
2- moderate pest security. This one is fine for new greenhouses, and light traffic GH's with cleanly guests. Once a pest gets inside, though, trouble trouble.
3- high security, meaning positive pressure and HEPA filters, thrips screening, humidity and temp control, haz-mat suits and dissinfect routines. Just the thought of all that work spoils my mood, but is probably the smartest long term plan for commercial use.

I'm a low security type guy. Address the pest directly. Mold? Increase airflow and temp, decrease humidity. Spider mites, fungus gnats, white flies, aphids? Allow predators, spray with tea, nuke them with CO2. Nasturtiums are awesome for the garden by the way; trap crop or aphids, pest predator magnets, repel white fly and spider mites. Yep. And borage, and multicropping.

 Vlad Jovanovic
Link to discussion.
You can use the 'ol 3-5% oil + 0.5% dish washing detergent well but you have to be real careful to get as little of the concoction into your system and take measure to cover up your FT to protect from overspray. And even this low % of oil will burn pepper plants if you have any...won't damage them beyond repair or anything, just don't be freaked out by the necrotic lesions that will be left on their leaves. peppers seem especially sensitive to this type of treatment.
A better/easier/more fish safe bet might be a naturally occurring fungus called Beauvaria bassiana that will take care of a whole host of common garden pests...spider mites included (and then some). B. bassiana can be purchased under the trade names Botaniguard, Naturalis-L or Mycotrol-O the later two being ok'd by OMRI...and more importantly it is fish safe (unlike any kind of oils or most soaps).
Whatever you spray with make sure to repeat after 3 or 4 days...then again after 3 or 4 days...and then once more...since most of these sprays wont kill the eggs that they've make sure you get the bastards that have hatched...and spray the under-sides of the leaves...Good luck. Spider mites are a royal PITA.
Here is a link to another in depth discussion about Botrytis cineria and Sclerotinia sclerotiorum
Botrytis blight (Botrytis paeoniae ) on peony (Paeonia officinalis ) - 5387709 Botrytis blight 
Sclerotinia rot (Sclerotinia sclerotiorum ) on cultivated tobacco - type unspecified (Nicotiana tabacum ) - 5424472 Sclerotinia rot

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