Summary of the Comparative Efficacy of Common Active Ingredients in Organic Insecticides Against Difficult to Control Insect Pests
There exists a lack of control efficacy information to enable decision-making about which organic insecticide product works best for a given insect pest. Here we summarize results of 153 field trials on the control efficacy of common active ingredients in organic insecticides against groups of the most difficult to control insect pests. The performance of organic products Entrust (spinosad), Azera (pyrethrin and azadirachtin), PyGanic (pyrethrin) and Neemix (azadirachtin) varied widely among pest groups, as well as among pest species within a group, providing an overall reduction in pest infestations by 73.9%, 61.7%, 48.6% and 46.1%, respectively.
Entrust was the most effective control option for many insect pests, particularly providing >75% control of flea beetles, Colorado potato beetle, cabbage worms and alfalfa weevil. However, Entrust was relatively ineffective against sucking insects, particularly true bugs and aphids. Resistance to spinosad has occurred in a number of insect pests, especially diamondback moths, several thrips species and Colorado potato beetles, so farmers should consider using other classes of insecticides in rotation with Entrust to reduce the risk of resistance development.
Azera provided >75% control of green peach aphid, flea beetles, Japanese beetle, Mexican bean beetle, potato leafhopper and cabbage worms. PyGanic was less effective than Entrust and Azera but still provided >75% control of green peach aphid, flea beetles and potato leafhopper. The growth inhibition effects of azadirachtin in Neemix were particularly effective against larvae of Mexican bean beetle and Colorado potato beetle but were generally less effective in trials with insect infestations consisting mainly of adult stages.
Thrips, stink bugs, cucumber beetles and fruitworms, were particularly difficult to control. Results seen in these studies may differ based on field size, infestation level, insect growth stage, as well as the number and timing of applications.
For more information about specific pests and crops the full article can be found at: https://www.mdpi.com/2075-4450/11/9/614
This article appears on May 13, 2021, Volume 12, Issue 2 of the Vegetable and Fruit News