A lot of plant lice here...

Maarten van Helden Maarten.vanhelden at medew.ento.wau.nl
Wed Jun 7 02:27:27 EST 1995

In article <7C4zvcD+LVVV083yn at champlaincollege.qc.ca>, 
lafranc at champlaincollege.qc.ca says...
>I have a problem: plant lice.  And a lot of them!!!! I tried a few things,
>but up to now it's unsuccessful.  Do you know any tips/products/anything
>so I can try to get rid of these little annoying insects???
>It's a shame that there's no coccinella anymore, 'cause they just eat those
>plant lice.  Is there a way to attracts (or "breed") coccinella?   Because
>I would prefer a more organic way to kill these lice than a chemical,
>polluting way.
I assume plant lice is the same as aphids in this case ??

Well, it's spring, aphids start early and outnumber predators easily. 
In temparate zones the population growth of predators and parasites should be 
sufficient to overtake the aphid population in a few weeks time from now. Look 
carefully at your plants, there should be plenty of coccinellid larvae around by 
now, you might even collect them in the field (roadsides etc) with a sweep-net and 
then select the larvae from the other insects you will catch (lot's of interesting 
creepy crawlers). However other enemies will also appear: larvae of gall midges 
(aphidoletes species), larvae of syrphids, earwigs, ground beetles etc. etc. There 
 is a very interesting book called "aphid predators" (the naturalist handbook, 
richmond publ, comp. Great britain). Also parasites like aphidoletes and pran 
species will lay eggs in the aphids and these will then turmn brown and become 
"mummies" from which new parasites emerge. Birds will eat a lot of aphids and 
strong rains will also help. 

You can attract predators by providing shelter (nesting mand overwintering sites) 
or alternative food (e.g. pollen) in many ways.

So, many environmentally sound solutions which will take over in a few weeks. Of 
course when you are a commercial grower you will prefer a chemical solution which 
is near 100% sure. However the natural solutions are very good, you hardly ever 
see a real aphids pest problem in a "natural" vergetation. Even house plants can 
be cleaned of aphids when you place them outside for a couple of weeks (provided 
that it's niot too cold or too sunny/hot). If you are interested to see how it 
works: Sit back and relax and let nature take it's course. It's a lot of fun !!!

||\\  //||  Dr. Maarten van Helden
|| \\// ||  Dept. of Entomology
||  \/  ||  Wageningen Agricultural University
||||||||||  Binnenhaven 7, 6709 PD
||      ||  Wageningen, the Netherlands
||      ||  Tel +31-8370-85118 Fax +31-8370-84821
||      ||  Email: <maarten.vanhelden at medew.ento.wau.nl>

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