The pesticide Paradox in IPM Risk-Benefit Analysis
IPM: is all about compatibility
Insecticides
Insecticide Definition Any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest (US EPA 2002)
It has been said in the 30s! “Biological and chemical control are considered…as the two edges of the same sword…nature’s own balance provides the major part of protection…insecticides should be used so as to interfere with natural control of pests as little as possible” (Hoskins et al 1939)
IPM remains compromising between: Environmental/human health advocacy Industries that need to use insecticides in order to prevent economic lost.
The impact of pesticides within IPM depends on: The pesticide The pest The management situation
Pesticides and Cotton
Boll-weevil eradication program
Pesticides are compatible with some IPM techniques Plowing Host-plant resistance Physical barriers
Pesticides and Bio-control Natural enemy resistance
Natural enemies tolerate different insecticides differently Variation observed within insecticides classes. Differential response of parasitoids versus predators.
Not only pesticides can interfere with IPM Bacillus thuringiensis Cinnibar moth feeding on tansy ragwood Gypsy moth Western Spruce budworm
Fungicides and herbicides might affect natural enemies
Fungicides and Bio-control
Sub-lethal effects Natural enemies might produce fewer viable eggs. Repellent effects
Colorado potato beetle and Beauveria bassiana
Purple loosetrife, beetles and mosquitoes Purple loosetrife Galerucella sp
Water Hyacinth weevils and herbicides
Insecticides are one of the four building blocks of IPM Chemical Biological Cultural Plant resistance IPM
Improving pesticide selectivity Timing e.g. Apply before the arrival of natural enemies Placement e.g. Apply in first two thirds of plant only. Apply insecticide to the middle of every other row. Pesticide application just next to seed.
Refuge!
Pesticides formulation might make a difference! Dust is more toxic to beneficials than wetable powders or emulsifiable concentrates.
Pesticides formulation might make a difference! Granular applications of certain pesticides do not reduce the number of natural enemies in certain crops but foliar applications of the same pesticide might cause substantial reductions.
Pesticides formulation might make a difference! Systemic pesticides will protect some natural enemies as well.
Pheromones are a good way to incorporate insecticide use in IPM
The greatest treath to many IPM programs is the misapplication of pesticides