Thrips
PESTS
require consuming up to 200 whitefly eggs per day in order to reproduce . Whiteflies also can be controlled via the parasitic wasps found within the genus Encarsia . Encarsia formosa is the most prevalent beneficial wasp used to control greenhouse whiteflies . These tiny insects inject their eggs into the bodies of whiteflies in the same manner as the Aphidoletes aphidimyza and Aphidius colemani do with aphids . Whitefly hosts generally die 10 days after being parasitized . The adult Encarsia will emerge from the dead whitefly in about another 10 days . To get a handle on whitefly infestations using sprays , pyrethrins and neem are two good options — insecticidal soap is another . For whitefly control , use a combination of different controls in successive sprays . It is nearly impossible to get full coverage in one application given the whitefly ’ s tendency to spook easily and fly off . Plan on at least three applications , possibly more .
Thrips
Thrips are similar to aphids and whiteflies in that they cause their damage by sucking as opposed to chewing . These small flying insects can be anywhere from clear , to black , to reddish orange in color . Along with their black deposits of frass , they are often found on the undersides of leaves . Like the other pests described here , there are numerous thrip species out there , each with their preferred host plants . Damage from thrips appears as a dappled , stippled or speckled leaf surface . Thrips will also feed on many fruits , which ends up causing damage to the entire crop . Thrips usually don ’ t kill their host plants ; they often cause stunted growth or poor performance as a result of the plant ’ s cellular losses and reduced ability to photosynthesize .
Controlling thrips using beneficial insects depends on the species you ’ re tackling . There are actually predatory thrip species that can be released to control the pest thrips . A positive identification of the pest species should be made before deciding on a beneficial insect to release . Predators such as the green lacewing ( Chrysoperla rufilabris ) and the minute pirate bug ( Macrotracheliella nigra ) will generally feed on multiple species of thrips . However , you cannot expect stellar results if you are releasing beneficial insects to control thrips on outdoor plants . They are much more effective when used to control thrip infestations indoors . The most effective spray for controlling thrips is spinosad , a naturally occurring fermented bacterium . This is the active ingredient in many insecticides approved for organic gardening . Unlike many non-synthetic pesticides , spinosad penetrates the leaf surface to reach the undersides where the thrips are feeding .
" Thrips usually don ’ t kill their host plants ; they often cause stunted growth or poor performance as a result of the plant ’ s cellular losses and reduced ability to photosynthesize ."
In Part II of our series on pest control , we will look at identifying damage from spider mites , fungus gnats and various caterpillars , as well as some of their biological and natural controls . Part III will detail how to control snails , slugs and other pests , as well as provide tips on attracting beneficial insects to your growing areas .
104 Maximum Yield USA | June 2016