Some Understanding and Knowledge of Orchid Pests: Orchid Mealybugs

Orchid mealybugs, also known as whiteflies (TRIALEURODES VAPORARIORUM), adults and nymphs gather on host leaves, suck sap, form yellow spots at the feeding sites, and can secrete honeydew, inducing sooty mold.

　　

Morphological characteristics:

　　

Adult body length about 1.1 mm, pale yellow, wings semi-transparent, both covered with white waxy powder. Eggs yellow. Nymphs small and flat, oval, pale yellow, covered with a semi-transparent waxy substance. Pupae oval, flat, yellow-green before emergence, pupal cases white and transparent after emergence. The dorsal surface of both nymphs and pupae bears waxy spines of varying lengths.

Life habits:

　　

It can produce 11~13 generations per year, overwintering as mature nymphs or pupae. Eggs are mostly laid on the underside of young host leaves. Newly hatched nymphs do not crawl far and mostly settle near the eggshell to feed and cause damage. Population density increases fastest in July~August, and damage is most severe in August~September. Adults are poor fliers and spread slowly, with obvious centers of infestation. Adults have a strong attraction to yellow.

　　

Control methods:

　　

For orchids grown in greenhouses, in winter spray at a dose of 1 ml of 80% dichlorvos original solution per cubic meter, then fumigate in a sealed environment, keep closed for 8 hours, then open windows for ventilation. Adults can be trapped and killed using orange-yellow sticky insect cards.

　　

Control pesticides:

　　

Choose 25% buprofezin wettable powder at 2000 times dilution, 25% thiamethoxam emulsifiable concentrate at 2500~3000 times dilution, 2.5% lambda-cyhalothrin emulsifiable concentrate at 3500 times dilution.