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Cotton mirid bugs still require priority control at present

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This year's cotton pest situation differs from previous years. For most of the cotton growing period, the first and second generations of cotton bollworm did not have too great an impact on cotton; it can be said that cotton bollworm did not break out on a large scale. However, in the later stage of cotton growth, some cotton farmers only focused on controlling summer aphids and did not pay attention to controlling other pests. In fact, pests in the later stage of cotton growth are often another important factor preventing high cotton yields. The main pest in the later stage of cotton growth is the cotton mirid bug, a hemipteran cotton pest with extremely strong reproductive capacity, whose damage period lasts from mid-May

This year's cotton pest situation differs from previous years. For most of the cotton growing period, the first and second generations of cotton bollworm did not have too great an impact on cotton; it can be said that cotton bollworm did not break out on a large scale. However, in the later stage of cotton growth, some cotton farmers only focused on controlling summer aphids and did not pay attention to controlling other pests. In fact, pests in the later stage of cotton growth are often another important factor preventing high cotton yields. The main pest in the later stage of cotton growth is the cotton mirid bug, a hemipteran cotton pest with extremely strong reproductive capacity, whose damage period lasts from mid-May all the way to early October. If not controlled in time, it will cause substantial yield reductions in cotton. Based on long-term experience guiding production in the fields, the author has summarized a good set of methods for controlling cotton mirid bugs, for the reference of fellow cotton farmers:

I. Techniques for controlling mirid bugs

1. Concentrated control. This is a control method used to prevent spread and damage, and its control effect is relatively good.

2. Carry out agricultural control well. Remove weeds in the field in time, strengthen cotton field management, prevent excessive growth, and reduce the base number of pest sources, etc.

3. Treatment must be thorough. Each chemical control application should achieve the effect of being "thorough, clean, and leaving no residual pests." After control, inspections should be carried out, and residual pests should be kept below the control threshold. When the pest population in the cotton field is relatively large, continuous and thorough treatment should be carried out to control the opportunity for mirid bugs to continue reproducing in the cotton field.

II. Seize the key periods. In our province, mirid bugs occur 5-6 generations a year. The first key control period is in mid-to-late May. When field inspection shows a newly damaged plant rate of 1%-2% (newly damaged plants are those with small black spots appearing on new true leaves at the cotton terminal bud) and 1-2 insects per 100 plants, control should begin. The second key control period is in early-to-mid June, when cotton enters the bud stage. When field inspection shows a newly damaged plant rate of 3%-5% and 3-5 insects per 100 plants, control should be carried out promptly. The first and second generations occur relatively uniformly, and as long as control is timely, they are relatively easy to bring under control. From late June, the hatching period of the third-generation nymphs begins. After that, the reproduction of mirid bugs shows overlapping generations, gradually with no obvious generational boundaries. In addition, as the cotton field becomes dense, it enters a particularly difficult control period. The main stem terminal bud and fruit branch terminal buds should be inspected in time. When the newly damaged plant rate in the field is 5%-10% and there are more than 5 insects per 100 plants, control should be carried out promptly, generally once every 7 days, until late September.

III. Use special-effect chemicals for control. In production practice, through repeated experiments on controlling mirid bugs, a compound pesticide of phoxim and malathion has the best effect. Phoxim is a highly effective and low-toxicity pesticide with a very strong knockdown effect on mirid bugs, but because its residual effect period is relatively short, long-term use alone will cause mirid bugs to develop resistance. Malathion has three effects: stomach poisoning, contact poisoning, and fumigation. It is a broad-spectrum insecticide. Although its efficacy lasts relatively long, its knockdown ability is not as good as that of phoxim. After these two chemicals are compounded, their advantages complement each other and the effect is best. It truly has a control effect on mirid bugs of "knocking them down as it goes." A pesticide specifically for controlling mirid bugs, "Jingruite" packet, can also be used. The method of use is: mix each packet with 15 kg of water and spray, and the control effect can last up to 20 days.

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