Beneficial insects in organic agriculture: citrus little helpers

Summary

The BIs against P. citri are well-perceived by consumers and do not represent a threat to the agroecosystem.
Practical recommendations
• BIs are reared inside climatic chambers and shipped to farmers pre-fed and pre-mated.
• For citrus, two BIs are commonly used: Leptomastix dactylopii and Cryptolaemus montrouzieri.
• The parasitoid L. dactylopii is very efficient against P. citri. Repeated releases over a short period should be done under warm, sunny, humid conditions when the first mealybug females move towards the top of the plant.
• The ladybug C. montrouzieri can wipe out large P. citri populations. 10-20 adults per plant is neces-sary in cases of high infestations (around 5,000 ladybugs/hectare in orchards). High prey density stimulates egg laying and prevents dispersion; hence ladybugs’ release is recommended in hot spots.
• Limiting factors (for both species) include temperatures below 17 °C or above 34 °C and the presence of ants.
• To ensure maximum BIs at the site, it is suggested to (i) mist plants with water before releasing and in the evening, (ii) reduce the use of sticky traps, and (iii) avoid white cloths.