The flowers of the blackberry bramble are susceptible to pest infestation. Though pests are generally not a cause for concern on blackberry plants, there are still instances that may cause severe damage. For successful fruit production, familiarize yourself with blackberry flower thrips and control methods. Maintain your blackberry bushes through appropriate care requirements for vigorous plants.
Vigorous plants are less vulnerable to pest infestations than stressed or ill plants. Maintain healthy blackberry plants by growing them in locations that provide full sun exposure. Though sunny locations are best, blackberries tolerate partial shade but develop poorly in heavy shade, according to the Oregon State University Extension. Blackberry bushes prefer extremely well-drained loam soil; waterlogged soil leads to decline.
Eastern flower thrips (Frankliniella tritici) are a common pest of blackberry flowers. These thrips display small bodies in brown or yellow hues. Measuring just under 1/16 inch in length, blackberry flower thrips choose many types of host plants including other brambles, apples and strawberries, according to the University of Illinois Extension.
Symptoms and Damage
Adult thrips feed on blackberry flowers through a feeding method called rasping. Rasping is a means through which thrips shred or scrape flower plant tissue, leaving it with a ragged appearance. Damage includes malformed or discolored fruit, flower wilt and flower drop, according to the University of Illinois Extension.
Before resorting to chemical control, natural control measures often decrease or eliminate pest infestations from blackberry bushes. For thrips, release predatory insects or parasitic wasps into the garden; these bugs hunt and kill thrips without causing any additional damage to your plants. Effective predatory insects include pirate bugs as well as lacewings in their larval stage. Purchase these predators from garden supply catalogs or stores.
For severe thrip infestations, the University of Florida Extension suggests applying an insecticide with the active ingredient malathion once a week. Begin at plant flush and continue treatment until harvest time. Chemical insecticides with the active ingredient pytrthrin are also an effective management method.