S. biformis larvae and adults feed on the leaf tissue, damaging infected parts. Leaves show silvery streaks and translucent epidermis marks. Both the larva and adult fold the leaf longitudinally to form a protective chamber. Typical symptoms also include stunting of the plant and the wilting and scorching of leaf tips, caused by by larval and adult feeding. In severe infestations, seedlings may be killed. Severe infestation during the panicle stage usually leads to unfilled grains.
The damage is caused by the feeding activity of the rice thrips, Stenchaetothrips biformis. In temperate areas, the insects migrate to and hibernate on weeds or other hosts from the Gramineae family during the winter season. They are also easily transported by the wind over long distances, to newly-planted rice fields. Females had a longevity of 13 days and during that time they lay about 25-150 eggs, primarily in the youngest leaf of the rice plant. Eggs are inserted into the slits of leaf blade tissue, the upper half remaining exposed. After hatching, young larvae feed on the soft tissues of unopened young leaves. Normally, all stages remain inside the rolled leaves, even the mobile adults. Periods of dry weather favor the development of the rice thrips and increase the severity of the damage. No standing water in the rice fields also encourages damage.
Encourage natural predators of S. biformis, such as predatory thrips, coccinellid beetles, anthocorid bugs, and staphylinid beetles. Neem oil also reduces thrips population significantly 48 hours after application. Flooding to submerge the infested field for 2 days as a cultural control practice is very effective against the rice thrips.
Always consider an integrated approach with preventive measures together with biological treatments if available. Seed treatment with thiamethoxam, phorate or carbofuron provides good control of the disease. Rice seeds should be soaked firstly in water for 8–10 h, then dried at room temperature, coated with the solution, soaked again in water and put to germinate. Compounds such as chlorpyrifos, dimethoate, monocrotophos, quinalphos, phosalone or carbaryl can be used in the nursery with good results.