Monday, June 17, 2013

Control of Mealybugs

In general, mealybugs are under good biological control. That is, because of the presence of a number of predators and parasites, this pest population is kept low.  There are, however, a number of factors that upset this balance. Two important factors are: the application of broad spectrum insecticides (BSI) and ants.  The application of BSI will not only kill the target pest but “the good bugs” as well.  When this happens, the resurgence of the pest can be worse than before. In addition, other pests, such as mites, will become a threat because their enemies have been eliminated.  

Ants also interfere with biological control because they protect the pest from its enemies.   By controlling the ants, the mealybug population will eventually diminish as the predators and parasites return. Although it takes time to work, even a couple of months, baits can be effective in controlling the ants.

For a quick solution, mealybugs may be sprayed with a soap and/or oil solution.  In addition, a high pressure stream of water from a garden hose will dislodge many of the pests.

Added note: mealybugs have filaments, or hairs around their body which protect them by repelling the spray droplets of  insecticides. Consequently,  a ‘spreader/sticker’ should be added to the spray solution. This product acts like soap to break down the surface tension and allow the liquid spray to spread out.  Spreader/stickers are necessary with most insecticidal applications but not when using soap and/or oil sprays. 

Photos by J.K.Clark, UCIPM