Banana-silvering thrips
Scientific name
Hercinothrips bicinctus
Description of adult
Banana-silvering thrips are small (1.5mm long), slender, brown insects with a darker abdomen and pale yellow hind wings that appear as a yellow line down the back of the body when the insect is at rest. Adult thrips have characteristic wings; the transparent wings have a fringe of hairs around the outside edge standing out in the same plane as the wing.
Immature stages
The tiny eggs are laid just into the plant tissue on the pseudostem or where 2 fruit touch. The nymphs hatch after 7–8 days, are pale yellow or white in colour and often have a black globule of excrement at the end of the abdomen.
Life history
The larval stage lasts about 10 days then the nymphs move down into the soil to pupate. Adults emerge after a further 7–10 days.
Distribution
A minor pest in southern Queensland and northern New South Wales. Only a single incidence has been recorded from bananas at South Johnstone in North Queensland.
Host range
Bananas, chokos, passionfruit and a number of weed species.
Damage
Minor and infrequent.
Feeding by these thrips causes silver speckling of green fruit that, on close inspection, can be seen to be speckled with dark excrement. In some instances browning of fruit may occur and deep longitudinal cracks may appear as a result.
Control
Usually only scattered plants are damaged.
Cultural
To prevent this insect spreading, do not use planting bits and suckers from areas infested with silvering thrips. Control important weed hosts, such as cobbler's pegs, in plantations to reduce infestations.
Biological
General predators such as ladybird beetles and lacewings keep silvering thrips in check.
Chemical
Spot spray if damage becomes excessive.
Chemical registrations and permits
Check the Australian Pesticides and Veterinary Medicines Authority database for chemicals registered or approved under permit to treat this pest on the target crop in your location. Always read the label and observe withholding periods.