Ladybirds Coccinella transversalis and Hippodamia variegata
Coccinella transversalis, or the Transverse Ladybird, is a predatory beetle native to Australia. This species has also been known as Coccinella repanda and Coccinella contempta.
Coccinella are found in all Australian states and territories, in India and across south eastern Asia. They inhabit urban areas, native vegetation and many agricultural crops. They are the most recognisable beneficial insect by the general public in Australia and are used as the logo of the ABC (Australasian Biological Control Inc.). Coccinella is a very useful biocontrol species as it is a generalist predator capable of feeding on a wide range of insect pest species including aphids, mites, scale insects, leafhoppers, moth eggs and small caterpillars.
Adults are convex, rounded bright orange/red ladybirds of 4-6mm in size. They have an orange head and a black pronotum (dorsal plate) with an orange marking along the front. The elytra (wing covers) are orange with a black stripe down the middle and two roughly “v” shaped markings on each wing cover.
Hippodamia variegata is a species of predatory beetle commonly known as the Variegated ladybird, Adonis ladybird, spotted Amber ladybird or White Collared ladybird. Originally native from Europe to Asia, it is now widely established in all continents. This species was first recorded in Queensland in 2000 and has since established throughout most of Australia and it can be prolific in vegetable crops and pastures.
Hippodamia are a generalist predator that prefer to feed on aphids but have the ability to eat a wide range of insect pests, including thrips, whitefly, scale insects, mites, mealybugs and moth eggs. Both adults and larvae eat large amounts of prey - up to 50 aphids per day.
Adults have slightly convex and elongated bodies and vary between 4–6 mm in length. They have black heads with white spots, white collar and dark eyes. The pronotum (dorsal plate) is black, with a white-yellowish border and a central black mask shaped marking. Their elytra (wing cases) are orange, with 3-15 black spots.
Ladybirds lay clusters of about 10-40 yellow, ovoid tapered eggs on leaves in areas where prey is plentiful. A female can lay 300-400 eggs in her lifetime, depending on nutrition. The eggs take around four days to hatch into larvae. The larvae are spiny, soft bodied, elongated (crocodile shaped), grey/black coloured with some orange markings. They feed for around 16 days, going through four larval instars (stages) and reaching a length of 6mm. The larvae then develop into black and orange pupae, usually on the underside of a leaf. After around seven days the pupae hatch into adult beetles that live for around 30-60 days. There can be several generations per year until winter when adult ladybirds can go through a dormant overwintering stage, depending on conditions. Both species are present throughout Australia showing they are capable of surviving a wide range of temperatures including Temperate, Mediteranean, and Subtropical conditions. The optimum temperature range for development is between 20-30°C. They consume most of their prey in the 4th instar and adult stages.
Ladybirds have the potential to be used in a variety of crops, both in protected cropping and in the field, to help control aphids. When established, they will also aid control of mites, scale insects, leafhoppers, moth eggs and small larvae. Ladybirds are beneficial in crops prone to aphid infestation such as roses, cereals, cotton, brassicas, melons, potatoes and capsicums. When prey numbers are low, they can persist in the crop, or in nearby vegetation by eating alternative prey species and pollen from flowers. The older larvae may become cannibalistic, eating the younger larvae, pupae or eggs if prey numbers become too low.
When to release
It is beneficial to have a resident population ladybirds in the crop to keep aphids or other pests in low numbers. When establishing a new crop, or when aphid numbers are high, additional releases will be needed. Ladybird establishment is more effective when pest densities are high as they have a plentiful food source. This can result in large numbers of beetles being produced, but sometimes honeydew and sooty mould can occur from the aphids prior to control being achieved. It is generally recommended to release Aphid parasites in conjunction with ladybirds prior to the pest becoming established.
How to release
Ladybirds are released in units of 100 eggs on cards which is the most cost-efficient way of releasing them. Best establishment will be achieved if you carefully place the egg cards onto plants with existing aphid infections.
If required, adult beetles are also available in punnets of 50 beetles with a small amount of honey or glucose to feed on during transit. Do not open the punnet until you are in the destination crop. Best results will be achieved if you carefully sprinkle 10-15 ladybirds next to each aphid infestation hot spot.
It is suggested to release ladybirds at inoculative rates into known areas of infestation, or at low levels throughout crops known to be prone to aphid attack. Release one card of approximately 50 eggs in direct proximity to a known aphid infection hotspot (1-2m²). For field release 1000 eggs/ha is suggested. Release each punnet of adults into 3-5 hotspots or at 500/ha if inoculating a whole crop. For both egg cards and adult beetles, several releases about two weeks apart are suggested.
For best results release egg cards or adult beetles into the crop as soon as possible after they are received, however, they can be stored for a few days at 8-12°C if necessary.
Adult ladybirds are quite tough, but at establishment are sensitive to many pesticides, particularly pyrethroids, organophosphates, neonicotinoids, oxadiazine and carbamate insecticides. Growth regulators such as Admiral and Applaud are also toxic. Residues on foliage and greenhouse structures may remain toxic for many weeks and negatively impact on their survival and ability to effect control. Check side-effects charts carefully and avoid using pesticides before and during use unless they are known to be safe. Contact Biological Services for specific information.
Ordering and accounts
Orders are sent via express courier services on Monday or Tuesday of each week, and usually arrive within a couple of days. Orders received after noon on Tuesday are sent the following Monday.
Accounts are sent at the end of each month, and can be paid by EFT, BPay, cheque or postal order.