dry rot/gnats

Johannes Ulrich Urban johannes-ulrich-urban@t-online.de
Wed, 15 Jun 2016 14:44:20 PDT
Hello Monica,

Thank you for your reply. I think you problem is different from mine but 
maybe this helps:

The term 'gnats' is difficult to translate for me, I looked it up and 
maybe it is comparable to an infection with Euopean Sciaridae insects. 
One variant of these tiny insects causes damage in moist conditions, the 
larvae feed on tender roots and destroy seedlings this way. In seed 
trays or propagators they find the right conditions: moist and warm. In 
the past they used to be treated with insecticides but with little 
success, mainly due to quickly developing resistance.
We now treat them with Steinernemia feltiae nematodes or Bacillus 
thuringensis israelensis. I tried the nematodes with very good result 
but not the Bacillus. I use the Bacillus on all kinds of caterpillars 
with excellent results. Both are not harmful to humans or pets or useful 
insects and are certified for ecological agriculture and are available 
commercially in Europe.
Some of the 'gnats' are also part of the Sciaridae family so maybe these 
treatments might also work for you.

I will further consider Dylan's advice on checking the compost moisture 
of stored dormant tubers next winter. Maybe it is a fungus that enters 
the tubers before they go  dormant, Begonias have lots of fleshy stems 
that often turn into a mush when the plant goes dormant. The plants shed 
these dying shoots but maybe the damaging agent is already in the tuber 
before the shoot is shed.

Thank your for your advice and ideas about this topic


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