bugs f r bugs Chilocorus - scale insect predators Chilocorus circumdatus larva feeding aggressively on white louse scale. (Photo: Chris Freebairn) Biocontrol organism Chilocorus circumdatus Chemical control of scale pests is difficult Red chilocorus is a helmet-shaped ladybird because they have hard, waxy protective beetle, about 5 mm long. The beetles covers and remain stationary for most of their are a rich orange colour with a fine black lives. Scale insects’ developing resistance to margin around the base of the wing covers. pesticides is an increasing problem in many Blue chilocorus is slightly smaller than red regions. chilocorus (about 3 mm long) and is a deep, metallic blue colour. Suitable crops/environments Like most beneficial insects, chilocorus prefer Adult female chilocorus lay cylindrical eggs environments protected from extremes of heat 1 mm beneath the cover of scale insects. At and low humidity and free from dust and toxic 25˚C, the eggs take about one week to hatch. pesticides. They can be used in enclosed and The larvae are voracious feeders and have in orchard situations. pronounced spines all over their bodies. After about ten days the larvae migrate to secluded positions and pupate. Adult beetles emerge between seven and nine days later to mate and start laying eggs about ten days after emergence. At an optimum temperature of around 28˚C, the life cycle takes approximately one month. Chilocorus beetles live for between four and eight weeks. Chilocorus circumdatus adult beetles. (Photo: Chris Freebairn) Target pests Armoured scale insects, including: Before release White louse scale (citrus snow scale) Unaspis citri Outdoor releases should be made early in Red scale Aonidiella aurantii the season before pest numbers have built Oriental scale Aonidiella orientalis up to damaging levels. Chilocorus should be Oleander scale Aspidiotus nerii released into indoor or nursery environments whenever scale insects are present. Best Scale-eating ladybirds prey on a range of results are obtained when a full release is armoured scale insects. Red chilocorus feeds made early in the season followed by regular readily on white louse scale (citrus snow ‘dribble’ releases at intervals of between three scale), oleander scale, oriental scale and red and six weeks.Like other beneficial insects, scale. Blue chilocorus prey on oriental scale cryptolaemus should be protected from and a range of other armoured scale species. extremes of heat and low humidity. Avoid using insecticides for at least two weeks Scale insects feed by sucking sap from before release. the plant. Heavy infestations may cause discolouration, leaf drop and shoot distortion., which can lead to twig dieback and even plant death. h Integrated Pest Management p/l 07 4165 4663 [email protected] www.bugsforbugs.com.au 1 bugs f r bugs Chilocorus - scale insect predators Recommended release rates Chemical use • Orchards: Minimum 20–50 punnets per Chilocorus beetles are very effective predators hectare. of scale insects but they may be harmed by • Enclosed situations: Minimum one punnet per pesticides. Copper and nutritional sprays will 20–50 m2. usually not harm them and some miticides are • Higher release rates may be required where also fairly safe. Carbamate, organophosphate there is a history of scale problems. and synthetic pyrethroid insecticides are toxic. If an insecticide has been applied, a minimum After release of four weeks should elapse before beetles are The beetles should rapidly disperse released. Where a clean-up scalicide is throughout the treated area when released. Adults will begin to consume scale insects warranted, an application of narrow-range immediately but it may be up to two weeks petroleum spray oil is recommended if before larvae can be observed feeding on the possible. pest. Drift of pesticides from neighbouring areas Regular monitoring by an experienced scout should be prevented. Some insect growth is recommended following release to check regulators (IGRs) are also toxic to predatory the beetles are established. Booster releases beetles. may be needed in crops with heavy scale infestations. Do not expect to see adult Other natural enemies of scales beetles readily after release. Note that the • The parasitic wasps Aphytis spp young larvae are very different from the adult • The parasitic wasps Comperiella spp beetles. • Green lacewings Mallada signata Cultural practices to aid establishment Excerpt from the Good Bug Book Practices that reduce wind and dust will help the beetles establish. Avoid releasing the beetles where bright lights may attract them away from the release area. In shopping centres and office blocks it is best to release beetles out of hours. High populations of ants may interfere with the predators and reduce their performance. In these situations ants should be controlled or excluded from the crop. Chilocorus circumdatus adult feeding on white louse scale on citrus. (Photo: Denis Crawford) h Integrated Pest Management p/l 07 4165 4663 [email protected] www.bugsforbugs.com.au 2.