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.
Armoured scale insects, including:
- Red scale Aonidiella aeranti
- Oriental scale Aonidiella orientalis
- Oleander scale Aspidiotus nerd
- White louse scale (citrus snow scale) Unaspis citric
Scale-eating ladybirds prey on a range of armoured scale insects. Red chilocorus feeds readily on white louse scale (citrus snow scale), oleander scale, oriental scale and red scale.
Scale insects feed by sucking sap from the plant. Heavy infestations may cause discolouration, leaf drop and shoot distortion, which can lead to twig dieback and even plant death.
Chemical control of scale pests is difficult because they have hard, waxy protective covers and remain stationary for most of their lives. The development of resistance to pesticides by scale insects is an increasing problem in many regions.
Like most beneficial insects, chilocorus prefer environments protected from extremes of heat and low humidity and free from dust and toxic pesticides. They can be used in enclosed and in orchard situations.
Outdoor releases should be made early in the season before pest numbers have built up to damaging levels. Chilocorus should be released into indoor or nursery environments whenever scale insects are present. Best results are obtained when a full release is made early in the season followed by regular half releases at intervals of between three and six weeks.
Chilocorus should be protected from extremes of heat and low humidity. Avoid using insecticides for at least two weeks before release.
Chilocorus are supplied in punnets containing a minimum of 50 beetles. The lids should be opened and the beetles dislodged by lightly tapping the container onto plant foliage near scale infestations.
Recommended release rates
- Orchards: minimum 20 to 50 punnets per hectare.
- Enclosed situations: minimum one punnet per 20 to 50 m2. Higher release rates may be required where there is a history of scale problems.
A note on release rates: Unlike chemicals which generally exhibit a clearly defined dose response curve, with beneficial insects, more is always better. However, they are costly to produce and the goal should be to achieve the best results at minimal cost. We are constantly trying to strike a balance between cost and efficacy. There are many factors that should be considered including the value of the crop, the magnitude of the pest population and the activity (or otherwise) of naturally occurring beneficial species. Also unlike chemicals, where it is common to respond to pest populations that have already exceeded some ‘economic threshold’, we recommend establishing beneficials early in the life of the crop before pest populations reach threatening levels. In most cases our releases are inoculative and we anticipate that our beneficials will establish and breed up within the crop to give long term control. As a general principle, 2-3 releases of modest numbers is better than a single large release – this reduces risk, improves establishment and accelerates the development of multiple overlapping generations of the beneficial species.
The beetles should rapidly disperse throughout the treated area when released. Adults will begin to consume scale insects immediately but it may be up to two weeks before larvae can be observed feeding on the pest.
Regular monitoring by an experienced scout is recommended following release to check the beetles are established. Booster releases may be needed in crops with heavy scale infestations. Do not expect to see adult beetles readily after release. Note that the larvae are very different from the adult beetles.
Cultural practices to aid establishment
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.
Ant control: 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. See our ant control blog article for more details.
Sleeve cages: When releasing adult ladybird beetles, we recommend the use of sleeve cages to aid in the establishment of a local breeding population. You can purchase our beetle bag sleeve cage product or view our tips for establishing a ladybird population blog article for details about how to make your own sleeve cage.
Chilocorus beetles are very effective predators of scale insects but they may be harmed by pesticides. Copper and nutritional sprays will usually not harm them and some miticides are also fairly safe. Carbamate, organophosphate and synthetic pyrethroid insecticides are toxic. If an insecticide has been applied, a minimum of four weeks should elapse before beetles are released. Where a clean-up scalicide is warranted, an application of narrow-range petroleum spray oil is recommended if possible.
Drift of pesticides from neighbouring areas should be prevented. Some insect growth regulators (IGRs) are also toxic to predatory beetles.
Chilocorus ladybird beetles are despatched by overnight courier or express post and should be received within one or two days. Honey is supplied as food for the beetles.
The beetles should be released as soon as possible after arrival. In the event of adverse weather such as extreme heat or high rainfall, they may be stored for several days before release. This is best done in a dark room at about 17°C. Extra honey should be placed under the lid if the original supply has already been consumed.