Yellow Stem Borer

  • Symptoms

  • Trigger

  • Biological Control

  • Chemical Control

  • Preventive Measures

Yellow Stem Borer

Scirpophaga incertulas

Insect


In a Nutshell

  • Feeding damage near the growing points cause deadheart of tillers.
  • During the reproductive stage, whitish unfilled panicles are observed.
  • Tiny holes, frass and fecal matter are left on the damaged stems and tillers.

Hosts

Rice

Symptoms

Feeding damage near the growing point causes deadheart and dead tillers at the vegetative stages and whiteheads (whitish unfilled panicles) at the reproductive stages. After hatching, the larvae bore into the leaf sheath and feed on the inner surface of the stem wall in the direction of the stem. Tiny holes, frass and fecal matter can be observed on the damaged stems and tillers. The larvae can move from one internode to another. Frequent larval feeding does not cause visible symptoms because the plant compensates for the damage by producing extra tillers. This costs energy and ultimately yield. The adults do not feed and live for 4-10 days.

Trigger

The yellow stem borer is a pest of deepwater rice. It is found in aquatic environments where there is continuous flooding. Second instar larvae wrap part of a leaf around their body and detach themselves from the plant, falling onto the water surface. They then attach themselves to the tiller and bore into the stem. High nitrogenous field favors population buildup. Fields planted later in the season favor the insect, whose population has built up in fields that have been planted earlier. Stubble that remains in the field can harbor stem borer larvae and or pupae.

Biological Control

Cutting the leaf-top before transplanting reduces the carry-over of eggs from the seedbed to the field. Raising the level of irrigation water submerges the eggs deposited on the lower parts of the plant and also helps to control the populations.

Chemical Control

Always consider an integrated approach with preventive measures together with biological treatments if available. Soak the roots of the seedlings in 0.02 % chlorpyriphos for 12-14 hrs before transplanting to give protection from the attack of stem borer up to 30 days. Pheromone traps may significantly decimate stem borer populations.

Preventive Measures

Use resistant varieties.,Monitor the seedbeds and fields regularly.,Handpick and destroy egg masses in seedbeds and during transplanting.,Raise level of irrigation water periodically.,Synchronize the planting in the area.,Harvest the crops at ground level remove the larvae in stubble.,Remove stubble and volunteer rice, plow and flood the field after harvest.,Apply nitrogen fertilizer in split applications.