What method should be used to treat sudden leaf drying in cowpeas
(1) Select good varieties and sow at the right time. The cowpea varieties that perform relatively well mainly include: Zhijiang 28-2, Zhangtang cowpea, and Hongzuiyan. For open-field direct sowing, sow in mid-to-late April; for seedling raising and transplanting, sow from late March to early April; for summer sowing, sow from late May to early June. (2) Land preparation, fertilization, and...
Shortly after the wheat harvest, some cowpeas show dry leaves and deformed leaves. The author's investigation found that these plots are mostly near cornfields, and the damage is caused by herbicide drift from spraying in cornfields. Herbicide drift from spraying in cornfields is mainly affected by wind; the stronger the wind, the farther the drift. Many vegetable growers treat this phytotoxicity as a disease, which not only fails to achieve the proper control effect but also delays the timing of control.Symptom expression
After herbicides are sprayed in cornfields, at first the old leaves of cowpeas dry up while the stems and vines remain green. As the cowpeas grow, new leaves become deformed, and the leaf surface is wrinkled and uneven. If the cowpeas are in the podding stage, flower drop occurs. The plants grow poorly, seriously affecting yield.
Control methods
Rinsing with clean water: the period when farmers spray herbicides is generally 7~10 days. During this period, water should often be sprayed on the stems and leaves of cowpeas to reduce the amount of herbicide residue on the stems and leaves of cowpeas.
Timely topdressing: topdressing should mainly use ammonium bicarbonate or urea, and some phosphorus and potassium fertilizer can also be appropriately added. The amount of topdressing should be determined according to the severity of the phytotoxicity and the growth of the cowpeas.
Watering sufficiently: water promptly after topdressing to promote the fertilizer effect to take effect as soon as possible and reduce the relative concentration of harmful substances in the cowpea plants. Foliar spraying of plant growth regulators and foliar fertilizer: the effect is better when spraying a mixed solution of brassin 7500-fold dilution plus foliar fertilizer. According to the degree of phytotoxicity, spray once every 10~15 days, and spray continuously 1~3 times.