A Complete Guide to the Prevention and Control of Common Soybean Pests and Diseases
Common Soybean Pests and Diseases and Their Control Techniques
(Agricultural Wealth Network) In recent years, soybean pests and diseases have occurred frequently, affecting soybean yield and quality. During the soybean growing period, the crop is damaged by many kinds of pests, causing reduced yield and lower quality. The damage characteristics and control techniques of several pests are introduced below.
1. Clanis bilineata (soybean hawk moth) The soybean hawk moth, commonly known as the soybean worm (also called "zhangmu worm"), damages soybean leaves as larvae, causing notches or holes; in mild cases the leaves are eaten into a network of holes, and in severe cases the soybean plants are stripped bare and cannot form pods, affecting yield. Generally, mid-to-late July to early August is the peak period for adult egg-laying, and late July to late August is the peak period for larval occurrence. Newly hatched larvae are photophobic and hide on the underside of leaves during the day. The 1st and 2nd instars damage the top parts by biting the leaf edges into notches and generally do not migrate. The 3rd and 4th instars greatly increase their food intake and move to other plants to cause damage; this is the suitable period for control. The 5th instar is the gluttonous feeding stage, accounting for about 90% of the food consumption during the larval stage. From June to August, coordinated rainfall favors the occurrence of the soybean hawk moth. In densely growing soybean plants and in low-lying, fertile soybean fields, adults lay more eggs and the damage is more severe.
Control method: Spray during the larval stage before the 3rd instar. Use 50% phoxim emulsion at 1000 times dilution or 20% fenvalerate at 2000 times dilution, or 20% fenvalerate emulsifiable concentrate or 2.5% deltamethrin emulsifiable concentrate at 2 000 times dilution, spraying 50 kg of solution per mu.
2. Soybean semilooper There are many species of soybean semilooper, with the silver-marked noctuid being the most common. The larvae damage soybean leaves, feeding on tender tips, flowers and young pods; they can eat all the leaves, causing flowers and pods to drop and seeds to be unfilled, seriously affecting yield. The semilooper can produce multiple generations each year, with damage being most severe especially from early to mid-July to mid-August. Adults hide by day and come out at night, are strongly phototactic, and prefer to lay eggs in densely growing soybean fields; eggs are mostly scattered on the underside of leaves on the upper part of the plants. Young larvae feed only on the leaf mesophyll, leaving the epidermis in a window-pane pattern. Older larvae feed on the upper tender leaves, making holes, and mostly cause damage at night.
Control method: Use 20% fenvalerate emulsifiable concentrate or 2.5% deltamethrin emulsifiable concentrate at 2 000 times dilution, spraying 40 kg per mu.
3. Weevil Weevils bite and feed on plant stems and leaves.
Control method: Spray evenly with 50% phoxim emulsifiable concentrate at 1500-2000 times dilution or 20% fenvalerate at 2000 times dilution.
4. Soybean pod borer The soybean pod borer, also called the soybean pod-boring moth, bores into pods as larvae. Before boring in, the larva makes a white silk web covering itself, usually entering from the seam of the pod, and the damaged seeds are bitten into grooves or left broken.
Control method: 10% cypermethrin emulsifiable concentrate, 35-45 ml per mu, or decamethrin emulsifiable concentrate, 0.5-1 g of active ingredient, diluted in 40 kg of water and sprayed evenly.
5. Soybean aphid It causes damage from the seedling stage onward, feeding on the growing points, tender leaves, tender stems and tender pods of the plant, spreading viruses, causing leaves to curl, growth to slow and the number of pods to decrease; severe occurrence at the seedling stage can cause the whole plant to die.
Control method: Spray evenly with 50% phoxim emulsifiable concentrate at 1500-2000 times dilution or 20% fenvalerate at 2000 times dilution.
1. Clanis bilineata (soybean hawk moth) The soybean hawk moth, commonly known as the soybean worm (also called "zhangmu worm"), damages soybean leaves as larvae, causing notches or holes; in mild cases the leaves are eaten into a network of holes, and in severe cases the soybean plants are stripped bare and cannot form pods, affecting yield. Generally, mid-to-late July to early August is the peak period for adult egg-laying, and late July to late August is the peak period for larval occurrence. Newly hatched larvae are photophobic and hide on the underside of leaves during the day. The 1st and 2nd instars damage the top parts by biting the leaf edges into notches and generally do not migrate. The 3rd and 4th instars greatly increase their food intake and move to other plants to cause damage; this is the suitable period for control. The 5th instar is the gluttonous feeding stage, accounting for about 90% of the food consumption during the larval stage. From June to August, coordinated rainfall favors the occurrence of the soybean hawk moth. In densely growing soybean plants and in low-lying, fertile soybean fields, adults lay more eggs and the damage is more severe.
Control method: Spray during the larval stage before the 3rd instar. Use 50% phoxim emulsion at 1000 times dilution or 20% fenvalerate at 2000 times dilution, or 20% fenvalerate emulsifiable concentrate or 2.5% deltamethrin emulsifiable concentrate at 2 000 times dilution, spraying 50 kg of solution per mu.
2. Soybean semilooper There are many species of soybean semilooper, with the silver-marked noctuid being the most common. The larvae damage soybean leaves, feeding on tender tips, flowers and young pods; they can eat all the leaves, causing flowers and pods to drop and seeds to be unfilled, seriously affecting yield. The semilooper can produce multiple generations each year, with damage being most severe especially from early to mid-July to mid-August. Adults hide by day and come out at night, are strongly phototactic, and prefer to lay eggs in densely growing soybean fields; eggs are mostly scattered on the underside of leaves on the upper part of the plants. Young larvae feed only on the leaf mesophyll, leaving the epidermis in a window-pane pattern. Older larvae feed on the upper tender leaves, making holes, and mostly cause damage at night.
Control method: Use 20% fenvalerate emulsifiable concentrate or 2.5% deltamethrin emulsifiable concentrate at 2 000 times dilution, spraying 40 kg per mu.
3. Weevil Weevils bite and feed on plant stems and leaves.
Control method: Spray evenly with 50% phoxim emulsifiable concentrate at 1500-2000 times dilution or 20% fenvalerate at 2000 times dilution.
4. Soybean pod borer The soybean pod borer, also called the soybean pod-boring moth, bores into pods as larvae. Before boring in, the larva makes a white silk web covering itself, usually entering from the seam of the pod, and the damaged seeds are bitten into grooves or left broken.
Control method: 10% cypermethrin emulsifiable concentrate, 35-45 ml per mu, or decamethrin emulsifiable concentrate, 0.5-1 g of active ingredient, diluted in 40 kg of water and sprayed evenly.
5. Soybean aphid It causes damage from the seedling stage onward, feeding on the growing points, tender leaves, tender stems and tender pods of the plant, spreading viruses, causing leaves to curl, growth to slow and the number of pods to decrease; severe occurrence at the seedling stage can cause the whole plant to die.
Control method: Spray evenly with 50% phoxim emulsifiable concentrate at 1500-2000 times dilution or 20% fenvalerate at 2000 times dilution.