Biological control against the new invasive Mealy-bug Delottococcus aberiae (BIOFRUITNET Practice Abstract)

Summary

Combining several measures with those enhancing natural predators can effectively reduce the population year after year.
Practical recommendation
• The pest is present all year round, but the most critical time to control is from the fruit set until it reaches two centimetres (April to June), when the fruit is no longer susceptible to deformation.
• D. aberiae adult females lay eggs on the ground and on trunks in spring, after which the newly emerged nymphs return to the tree canopy. Males and females of a soil-dwelling mite, Gaeolaelaps (Hypoaspis) aculeifer (Picture 2), prey on the first instar nymphs of D. aberiae mealybugs. Therefore, enhance the presence of this soil predatory mite by adding compost or mulching. The presence of ground cover can also enhance the presence of these predatory mites.
• Release Cryptolaemus montrouzieri on the citrus canopy of the predator (Picture 1) from March onwards and at the larval stage (dose of 3/10 per tree, representing 1200-4000 adults/ha), to reduce pest levels at the time of maximum fruit sensitivity. Releasing adults in summer (Picture 3) at a dose of 3/10 per tree reduces the wintering population and, therefore, the levels of the following year.
• On-farm rearing of C. montrouzieri is carried out on potato sprouts filled with Planococcus citri.