Re: Aphids and Whiteflies

Juerg Steiger (steiger@iae.unibe.ch)
Sun, 11 Feb 1996 21:52:24 +0000

Each summer my several hundred Pings are infested by aphids, sometimes also
by whiteflies. Winged green and black female aphids from the garden
penetrate the greenhouse and their parthenogenetical reproduction is very
efficient. As removing them manually is very time consuming I made trials
with pyrethrum, ladybug larvae, Aphidius and Encarsia. Pyrethrum: kills the
Pings if used in usual dilution but doesn't kill the aphids in higher
dilution. Ladybug larvae: are mostly captured as soon as they climbe on
the upper leaf side. Aphidius (parasitic wasp): Kills green aphids, but not
the black ones. Works quite well, although two thirds are captured by the
Ping. leaves, but enough succeed to lay their eggs into the Aphids which
are usually on the underside of the leaves. Encarsia formosa (parasitic
wasp): Kills whiteflies. Same effect as Aphidius. Here you get Aphidius and
Encarsia kits for 40 squaremeters (greenhouse ground surface). An Aphidius
kit contains 500 wasps, an Encarsia kit 300 pupae. The remaining problem
are the black aphids which I remove manually, but they are at least better
visible than the green ones. Juerg

___________________________________________________
Juerg Steiger, Institut fuer Aus-, Weiter- und Fortbildung IAWF
University of Bern, Inselspital 37a, CH-3010 Bern, Switzerland
Office: ++41 31 632 98 87, Fax: ++41 31 632 98 71