Prevention and control of cotton blind Toona sinensis

The occurrence of blind stink bug is very sensitive to the ecological environment. The blind Toona sinensis likes the temperature of 25 ℃ ~ 30 ℃ and the relative humidity of 80% to 90%. The recent wet weather is very beneficial to the occurrence of the blind Toona sinensis. The planting of flower arrangement in cotton field is also beneficial to the parasitism and transfer of Toona sinensis. Now, soybeans, broad beans and other vegetables are interspersed in cotton fields, which is beneficial to their reproduction. Therefore, some cotton farmers in Hanchuan, Yunmeng and other counties and cities in Hubei Province have recently revealed that the occurrence and harm of blind stink bugs have emerged, and we must attach great importance to them.

There are many species of Toona sinensis, and the main ones that damage cotton are green bug, alfalfa bug, black bug, three-spot bug and so on. It can do harm at all stages of cotton growth and development. The harmful effects of Toona sinensis are as follows: one is to pierce the young organs of cotton plants with piercing mouthparts to absorb the juice of tender meat tissue, and the other is to inject saliva into the young organs of cotton plants, resulting in cell necrosis or abnormal growth. After the cotton cotyledon stage is harmful to the growing point, the injured tip dries up and no longer grows new buds, commonly known as male cotton; when 3 or 5 true leaves are damaged in the seedling stage, the terminal bud will also be stabbed and withered, but new buds can be sent out between the axils of the leaves to regenerate secondary fruit branches to form multiple heads of cotton, which is called broken head madness in some places; when the young leaves are killed, the leaves first show small black spots, and then the holes become irregular holes, commonly known as broken leaf madness. When the top of the fruit branch is killed, the leaf armpit will breed vegetative branches and form broom seedlings; the young buds will dry up after 2-3 days, the other is the bracts open, and then the young buds fall off, the third is that the big buds show black spots, and the flowers can not open normally; the young bolls are damaged, the epidermis shows dark-brown water stains, the heavy cotton bolls become rigid and fall off, or are covered with black spots, resulting in a decline in quality.

In view of the lessons learned from the harm caused by the blind Toona sinensis over the years, various localities have predicted that there is a great trend of occurrence this year, so we should take precautions as soon as possible. In terms of agricultural control, the first is to remove weeds around the cotton field; the second is to dredge the ditch box of the cotton field to reduce humidity; the third is to apply regulation and control means to shape the ventilated and transparent cotton plant type; the fourth is to reduce nitrogen fertilizer and increase the application of phosphorus and potassium fertilizer. In terms of chemical control, one can use 25% imidacloprid and mineral oil 1000 × 1500 times, 2% methylaminoavermectin benzoate wettable liquid 5000 times, acetamiprid 3% EC 1500 × 2000, 4% imidacloprid 5% imidacloprid 1500 times, 5% Liansheng suspension 5 000 times, 6% Kuailing 8000 times Seven can use 40% chlorpyrifos or 48% Lesbon EC 1000-1500 times. All kinds of permethrin EC can also be used.

The above medicines can be selected and applied according to the local reality, but they should be used interchangeably. In terms of application technology, the time of control should be advanced, generally from late May to early June, combined with the control of other pests for 3 or 4 times. When spraying, first spray from all around the cotton field, and then spray the cotton in the middle of the field to prevent the blind Toona sinensis from escaping. As the activities of the blind Toona sinensis are mostly at night, it is better to spray after 5 pm.