Differences Between the Rice Stem Borer and the Yellow Stem Borer and the Timing of Yellow Stem Borer Control

Rice is the food we are most familiar with, and it is currently distributed in many parts of our country, and growing rice is also a fairly popular activity. However, when growing rice, there are also many points that need attention, such as the common rice yellow stem borer and striped stem borer pests. But what differences are there between the two?

When is the timing for controlling the rice yellow stem borer

The best timing for controlling the rice yellow stem borer must be determined by two aspects: pest conditions and seedling conditions. When controlling deadheart seedlings, pest conditions are the main factor, that is, pesticide application during the peak hatching period of egg masses. The second day after 50% of the egg mass bottoms turn black is the peak hatching period, and it is the best period for controlling deadheart seedlings; when controlling whiteheads, seedling conditions are the main factor, that is, within the suitable control period, observe the rice growth stage, and reaching the booting and heading stage is the best period for controlling whiteheads. Because various pesticides have different speeds of action, biological pesticides should be applied appropriately earlier.

What are the differences between the rice striped stem borer and the yellow stem borer

1. The striped stem borer is larger in form than the yellow stem borer, the forewings are nearly rectangular, the hindwings are white, and there are seven small black dots on the outer margin; the yellow stem borer has a not very obvious black spot at the lower corner of the discal cell.

2. The striped stem borer larva has 5 dark brown longitudinal lines on its back; the yellow stem borer in the early first instar has a black head and a pale black thorax and abdomen.

3. The striped stem borer egg mass is flat and oval, with egg masses arranged irregularly like fish scales; the yellow stem borer egg mass has three layers of eggs, shaped like half a soybean.

4. In the seedling and tillering stages, the striped stem borer lays eggs on the upper surface of leaves 3--7CM from the leaf tip; in the late tillering stage, it lays them on leaf sheaths more than 6CM above the water surface. Yellow stem borer egg masses are mostly laid on leaf blades, and secondarily on leaf sheaths. On rice plants in the seedling and tillering stages, egg masses are mostly near the leaf tip, located in the center of the leaf surface. On rice plants in the main field in the middle and late stages, 80--90% of egg masses are mostly laid on one side of the midrib on the back of the middle part of the leaf blade. After heading, eggs are rarely laid, limited only to green flag leaves.

5. The striped stem borer has a stronger ability to bore into and damage rice than the yellow stem borer, and its invasion rate is also relatively high during the round-stem stage, and it can also bore into and damage rice during the heading and maturity stages.

Damage characteristics of the rice yellow stem borer

In recent years, the serious damage caused by the yellow stem borer has shown an upward trend again, and the reasons are manifold. Damage by the yellow stem borer causes deadheart seedlings. During the seedling and tillering stages, larvae gnaw on the central leaves. When the central leaves are damaged or lose water and roll longitudinally, they slightly fade green or appear blue-white, resembling a scallion tube in shape, called false deadheart. If the curled central leaves are pulled out, the cut edge can be seen to be neat, and larvae are often visible. After the growing point is destroyed, the false deadheart turns yellow and dies, becoming a deadheart seedling, while other leaves remain green. The boring hole in damaged rice plants is small, there is no insect frass outside the hole, and there is white fine-grained insect frass inside the stem. This differs from the deadheart seedlings caused by damage from the pink stem borer and striped stem borer.

Agricultural control methods for the rice yellow stem borer

1. Appropriately adjust the rice layout, avoid mixed planting, and reduce bridge fields.

2. Select varieties with a moderate growth period.

3. Carry out spring plowing and field soaking in time, handle rice stubble well, and reduce overwintering insect populations.

4. Choose rice fields or dry land without stem borer damage or with light stem borer damage as green manure seed fields. In production, because spring plowing in green manure seed fields is late, the vast majority of larvae have already pupated and emerged before plowing, so attention must be paid in production to eliminating the source of insects.

5. Irrigating winter crop fields and green manure fields with running horse water is not only beneficial to crop growth, but can also kill most overwintering stem borers.

6. Carry out spring plowing and irrigation in time, submerging rice stubble for 7—10 days, which can drown overwintering larvae and pupae.

7. Cultivation-based stem borer control. Adjust the transplanting period and adopt the seedling-throwing method so that the growth stages vulnerable to ant larvae damage are staggered from the peak hatching period of ant larvae, which can avoid or reduce damage.

In fact, as long as you understand the rice yellow stem borer and striped stem borer, it is still quite easy to distinguish them. When controlling the rice yellow stem borer, special attention must be paid to timing. In addition to timely control, usual prevention is also very important. Only by doing these well can rice be ensured to grow better.