2015 Autumn Grain Harvest Approaching: Manage Well to Boost Yields

Editor's note: Due to the abnormal climate this year, with drought and little rain early on and continuous rain later, the seedling conditions of autumn grain crops, especially dryland grain crops, vary greatly, making crop management considerably more difficult, creating conditions for the occurrence of pests and diseases, and proving rather unfavorable to crop growth. In view of this actual situation, this issue specially compiles a set of late-stage management techniques for autumn grain crops, hoping to provide help to farmer friends.

Rice

Strengthen Integrated Pest and Disease Control in the Late Stage

At present, large areas of rice are maturing one after another, and the harvest work is about to begin. However, due to differences in transplanting seasons between regions and other reasons, some rice is still at the heading to full-heading stage, and some is at the jointing-booting stage, which is a period prone to pests and diseases such as rice planthoppers, neck blast, bacterial leaf blight, and sheath blight.

Brown planthopper. According to surveys, brown planthopper occurs commonly on rice, and some severely affected fields have already shown patchy collapse. Because the rice's ability to absorb chemicals declines in the late stage, spraying systemic insecticides has a significantly reduced control effect on brown planthopper. It is best to use the toxic soil method for control, that is, use 100 grams of 80% dichlorvos emulsifiable concentrate per mu, add 1.5-2.5 kg of water to dilute, then mix with 25-30 kg of fine soil or fine sand to prepare toxic soil, and broadcast it into the rice field. Drain the field water before broadcasting the toxic soil.

Bacterial leaf blight. Rice bacterial leaf blight is a serious bacterial disease on rice, and the pathogen spreads via rainwater and flowing water. It has already occurred over large areas in low-lying fields. For affected fields, farmers should immediately be organized to carry out unified prevention and control using drugs such as ye ku zhao and streptomycin sulfate.

Rice leaf roller. During surveys, larvae of the rice leaf roller have already been found causing damage in some rice fields, and many adults are also present on rice clumps and field ridge weeds. Technical personnel should strengthen field surveys and promptly report the local occurrence and damage of this pest, while organizing farmers to control it.

Neck blast. In the surveys, no fields with relatively severe neck blast have yet been found, but since mid-July there has been continuous long-duration rainfall. Cloudy and rainy weather with little sunshine easily causes neck blast damage, so farmers should be organized to spray chemicals preventively on sunny days on rice at the booting and heading stages.

Sheath blight. In the surveys, sheath blight occurs commonly in the fields, and in some severe areas it has already infected the panicles. Because the wounds on rice caused by brown planthopper feeding and egg laying are favorable for the expansion and spread of sheath blight on the plants, fields with severe sheath blight also easily attract brown planthopper to feed. Therefore, control of both sheath blight and rice planthopper should be strengthened at the same time.

According to the current occurrence of brown planthopper, bacterial leaf blight, neck blast, sheath blight, and rice leaf roller, strengthening rice field management and the control of the above pests and diseases is already urgent. Technical personnel in each township should, according to local rice production realities, continue to strengthen field patrol inspections, promptly grasp the local occurrence of rice pests and diseases, and make use of intermittent sunny days to seriously organize farmers to carry out control work against rice blast, rice planthopper, bacterial leaf blight, sheath blight, and other pests and diseases.

Control agents. For bacterial leaf blight, choose ye ku zhao, agricultural streptomycin, copper succinate-glutarate, etc.; for rice blast, choose isoprothiolane, prochloraz, tricyclazole, etc.; for rice planthopper, choose 80% dichlorvos mixed with toxic soil, etc.; for sheath blight, choose propiconazole, validamycin, etc.; for rice stem maggot, armyworm, and rice leaf roller, choose emamectin benzoate, chlorpyrifos, etofenprox, etc.

To improve the control effect, the following points should be noted during control: 1. Field water must be drained before spraying. 2. Each mu must be sprayed with a full 3 buckets of spray liquid (45 kg), and sprayed evenly. When controlling sheath blight, the liquid should be sprayed onto the diseased parts at the lower part of the plants. 3. If rain occurs within three hours after application, supplemental application should be carried out promptly after the weather clears. 4. It is best to carry out unified prevention and control with the natural village or area as the unit. 5. Rice affected by rice blast and rice stem maggot grows relatively slowly, and adding rice dwarfing revival king during control will make the effect more obvious. For farmers in mountainous areas, adding rice dwarfing revival king to the spray liquid for controlling rice pests and diseases can not only improve the control effect, but is also more conducive to rice tillering and rooting, promoting robust rice growth.

Potato

Focus on Pest and Disease Control

The main disease of potato is late blight, which is the principal disease of potato. Leaves, stems, and tubers can all be damaged; when dry, the lesions turn brown and brittle, with no mold layer. The epidemic of late blight is closely related to climatic conditions and growth stages. If continuous rainy weather occurs after tuber formation and the temperature is suitable, the disease can spread throughout the entire field within 10 days, causing severe losses. The control measure is that if infected late blight plants are found during the growing period, chemicals should be sprayed promptly for control. A 1000-fold solution of 50% mancozeb wettable powder or an 800-fold solution of 25% metalaxyl wettable powder can be used for control. Apply once every 7 days, spraying 3-4 times consecutively.

The main insect pest of potato is the aphid, one of the major insect pests damaging potato. It has strong reproductive capacity, mainly damages leaves and tender shoots, and is also a major vector for spreading viral diseases. There are also the 28-spotted ladybird and underground pests. The main control methods are: for aphids, use an 800-fold solution of 40% omethoate or a 1000-fold solution of 10% aphid-planthopper all-in-one net (imidacloprid) wettable powder for control; for the 28-spotted ladybird, use a 500-fold solution of 80% trichlorfon or a 1000-fold solution of dimethoate for spray control, starting control as soon as adults are found; underground pests are mainly mole crickets, grubs, and cutworms. Use 500 grams of 80% trichlorfon wettable powder, dissolve it in water, then mix it evenly with 20 kg of roasted cottonseed cake or rapeseed cake or wheat bran to make toxic bait, and scatter it on the ground near the roots of seedlings in the evening to trap and kill them, or use phoxim granules 812 powder and apply it into the soil along with sowing for control.

Soybean

High Fertilizer and Water Needs in the Middle and Late Stages

Topdress flower-pod fertilizer as appropriate. From flowering to the seed-filling stage is the peak period of fertilizer demand. For fields with insufficient fertility and fertilizer deficiency, topdressing should be done promptly. Topdressing 15-20 kg of diammonium per mu can achieve an obvious yield-increasing effect.

Rational chemical regulation. If there is a tendency toward excessive growth, at the early flowering stage use 40-50 grams of 15% paclobutrazol per mu, add 50 kg of water, and spray on the leaves, or use 15 ml of 25% mepiquat chloride aqueous solution mixed with 50 kg of water for spraying. If excessive growth still occurs at the full flowering stage, a second growth-control treatment can be carried out.

Drought resistance and waterlogging prevention. From the early flowering stage to the pod-filling stage of soybean, if drought occurs, irrigate promptly; if waterlogging occurs, pay attention to drainage to avoid worsening disease.

Spray foliar fertilizer. In addition to the three major elements nitrogen, phosphorus, and potassium, boron, zinc, and molybdenum are indispensable trace elements for soybean. Therefore, spraying a multi-element compound nutrient solution from the flowering to seed-filling stage of soybean has the effect of increasing pods, increasing seeds, and raising yield. The method is: per mu, use 100 grams of monopotassium phosphate, 50 grams of zinc phosphate, 50 grams of borax (first dissolve it in hot water), and 25 grams of ammonium molybdate, stir fully to prepare the liquid, add 50 kg of water, and spray evenly on the front and back sides of soybean leaves, spraying 2-3 times consecutively.

Pest and disease control. The main insect pests of soybean to control are: 1. Soybean pod borer, spray with a 1500-2000-fold solution of 2.5% deltamethrin emulsifiable concentrate; 2. Clanis bilineata, spray with a 2500-3000-fold solution of 20% fenvalerate emulsifiable concentrate; 3. Soybean pod moth, spray with a 1000-1500-fold solution of 50% fenitrothion emulsifiable concentrate. The main soybean disease to control is: gray leaf spot, spray with a 500-600-fold solution of 70% thiophanate-methyl wettable powder or a 500-fold solution of 50% thiram wettable powder.

Corn

Topdress Well and Irrigate Well

Topdress grain-promoting fertilizer. To keep leaf function vigorous throughout, prevent premature aging, and promptly supplement nitrogen fertilizer, you can also use monopotassium phosphate or urea for foliar topdressing, so as to maintain and prolong the functional time of the leaves in the middle and lower parts and above the ear position, manufacture more compounds, promote grain formation, and make the grains plump and increase the 1000-grain weight; foliar spray with 1.5 kg of monopotassium phosphate, mixed with 100 kg of water per mu.

Irrigate with grain-filling water. Corn needs more water from heading to the milk-ripe stage. If drought occurs in this period, irrigate promptly to increase the seed-setting rate, promote water movement, and improve grain plumpness.

Alternate-row detasseling. Timely alternate-row detasseling can increase ear length and ear weight, raise the double-ear rate somewhat, relatively shorten the plants, improve field ventilation and light penetration, increase photosynthetic productivity, and raise yield.

Pest and disease control. 1. Corn aphid: spray with a 2000-4000-fold solution of 10% imidacloprid wettable powder or a 2000-2500-fold solution of 3% acetamiprid emulsifiable concentrate. 2. Corn borer: use 20-40 ml of 1.8% abamectin emulsifiable concentrate or 200-250 ml of 20% phoxim emulsifiable concentrate, mix with 40-50 kg of water, and spray for control. 3. Corn northern and southern leaf blight: spray with a 1000-fold solution of 70% thiophanate-methyl, or a 1000-fold solution of 75% chlorothalonil powder for control. 4. Corn rust: per mu, use 75-100 ml of 20% triadimefon emulsifiable concentrate or 60-70 grams of 12.5% diniconazole wettable powder, mix with 30-40 kg of water, and spray.