How to get rid of small leaf-rolling caterpillars

Rice leaf rollers can cause outbreaks of rice pests in the northern provinces. It is necessary to rely on notifications from local plant protection stations regarding the peak emergence and hatching times of the small rice leaf roller moths to determine the appropriate time for spraying. However, the specific hatching times vary from one field to another depending on the planting season and local microclimate.

Method 1:In the morning, around 9-10 a.m. (start monitoring 2-3 days before the peak butterfly season as announced by the local plant protection station, or on days when you see many butterflies attracted to lights in households near rice fields), use a stick 1.5-2m long to chase the butterflies away from the embankment, 2-3m from the edge. Do this about once every two days. Observe a gradual increase in butterfly density. If you see a sudden drop in density after the next chase, then two days later is the appropriate time to spray pesticides.

Method 2To check for newly hatched rice leaf roller eggs, observe that when you repel moths and notice a significant decrease in moth density compared to the previous time, inspect two points in the field 2-3m apart, each point covering 1m². Newly hatched rice leaf rollers (ages 1-2) are found at the tips of rice leaves that have curled into a sheath. The larvae are about the size of a small toothpick, light green in color, 0.3-0.7cm long, and very mobile. When you see more than 10 larvae/m², it's time to spray insecticide.

Using new insecticides that the pests are not yet resistant to, such as Virtako; Tasodant or common insecticides like Regent 800WG, Regill 800WG, Targo 800WG, Rhionin 800WG, Patox 95SP, Sattrungdan 95WP, Silsau 3.6WP (Abamectin 36EC, Aremec 36EC, Sherpatin 36EC), also yields good results. However, rice leaf rollers quickly develop resistance to insecticides. If an insecticide has been used 2-3 times, subsequent applications may require increased dosage or a different insecticide. Mixing two insecticides may also be more effective.

A second spraying should be done 3-5 days after the first in the cool afternoon if the pest density is high and eggs are hatching sporadically. Once the rice grains are filling, the small leaf-rolling caterpillars will no longer cause damage.

According toAgriculture Newspaper