Cabbage Integrated Pest Management : An Ecological Guide.

Ecology of Insect Pests and Natural EnemiesThe next table gives examples of a number of factors involved in decision making for ETL and for AESA.(picture from Fliert and Braun)ETLAESA● cost of control ● growth stage● harvest value of crop (estimation) ● weather conditions● loss of income due to pests (estimation) ● crop development factors (incl. compensation ability)● type and number of insect pests●●●●●●●●●type and amount of diseasestype and number of natural enemiestype and amount of natural disease control agentswater availability (irrigation, drainage)type and amount of weedssoil fertility statusfertilizer applicationsactivities in the field since last weekother observationsEconomic Threshold Levels may give a very general indication for the number of insects that canbe tolerated on a crop but they are seldom specific for the situation in your field today. Be verycritical to these threshold levels and monitor your field regularly to check for yourself in yourown field what decisions need to be taken4.11.4 Use of botanical pesticidesSome plants have components in the plant sap that are toxic to insects. When extractedfrom plants, these chemicals are called botanicals. Generally botanicals degrade morerapidly than most conventional pesticides, and they are therefore considered relativelyenvironmentally safe and less likely to kill beneficials than insecticides with longer residualactivity. Because they generally degrade within a few days, and sometimes within a fewhours, botanicals must be applied more often. More frequent application, plus highercosts of production usually makes botanicals more expensive to usethan synthetic insecticides. When they can be produced locally theymay be cheaper to use than synthetic insecticides. Toxicity to otherorganisms is variable, although as a group, they tend to be less toxic tomammals (with the exception of nicotine) than non-botanicals.Cabbage Ecological Guide - 200064