Ask Your PCA: What tools work best to control mealybugs and red scale?

By Chris Boisseranc
Southwest Ag Consulting, Inc., Redlands

Mealybugs and red scale are damaging pests for citrus production. Besides citrus thrips, red scale is probably one of the more predominant citrus pests in California. 

With red scale, pheromone disruption is available and effective. Traps are set in the trees, blocking the scent of the females, so the males can’t find them. There is also organic oil and conventional sprays for red scale, as well as a parasite called Aphytis melinus.

Red scale damages tree branches and affects future production. The pest mounts itself on the fruit and cascades down, leaving reddish-orange spots, downgrading the fruit.

Mealybugs move from the interior trunk wood into fruit clusters after the flowering stage. They embed themselves around the calyx of the flower, where thrips and red scale live, then cascade down the top and move between the clusters, causing cosmetic damage that can eventually soften the fruit.

Mealybugs don’t have pheromone disruption, but there are organic and conventional chemical controls. Organic growers have an oil method that suffocates the pest, and conventional growers have effective synthetic materials. There is biocontrol, too—a wasp called Anagyrus. 

Conventional spray applications can harm beneficial insects. Growers doing conventional applications may not do biocontrol releases, which may be done earlier in the season to gauge how effective they are. A spray application for red scale or mealybug should be based on the effectiveness of early-season biocontrol. 

Movento is used for red scale and mealybug control. Oil is included in the same tank mix. Movento is one the most effective materials for the two pests. Typically in inland and low-pressure areas, one application of Movento and oil is enough to control mealybugs and red scale throughout the season.