How to control cutworms? Master these methods for good results

Cutworms, also known as root-cutting worms, night thief worms, commonly called ground silkworms, soil silkworms, etc., are insects of the family Noctuidae, with about 1600 species in China. The adults have well-developed mouthparts and are polyphagous crop pests. More than 10 species cause damage to agricultural crops, among which the black cutworm, yellow cutworm, large cutworm, white-edged cutworm and greasy cutworm are particularly important. Let's take a look below at how to control cutworms!

Living habits of cutworms

The phototaxis and chemotaxis of adult cutworms vary by species. The black cutworm, yellow cutworm and white-edged cutworm all have taxis to black light lamps. The taxis to sugar-wine-vinegar liquid is strongest in the black cutworm, while the yellow cutworm prefers to feed on scallion flower stamens as supplementary nutrition. Eggs are mostly laid on the soil surface, on young tender stems and leaves of plants, and at the root zone of dry grass, either scattered or in clusters. Larvae before the 3rd instar mostly move on the soil surface or on plants, feeding day and night on leaves, heart leaves, tender tips, young buds and other parts, with a relatively small amount of feeding. After the 3rd instar they disperse into the soil, hiding in the soil during the day and becoming active at night to cause damage, often biting off crop seedlings at ground level, causing missing plants and broken rows, and they exhibit cannibalism.

Damage characteristics of cutworms

Cutworms are one of the polyphagous crop pests. More than 10 species cause losses to crops, and all of them damage the aboveground stems of Fritillaria ussuriensis as larvae, often biting off the stems at the soil surface and causing the plants to die, resulting in missing plants and broken rows. Their main hosts and damaged crops include corn, sorghum, wheat, potatoes, beans, hemp, tobacco, rapeseed, cucurbits and various vegetables, etc. Many weeds are also important hosts of cutworms, and vegetable seedlings are also often damaged.

How to control cutworms?

1. Paulownia leaf trapping method: Cutworm larvae have taxis to paulownia leaves. Take older paulownia leaves, soak them in clean water, and place them in the field in the evening, 80-120 leaves per mu. The next morning, lift the leaves and catch the larvae; the effect is very good. If the paulownia leaves are first soaked thoroughly in a 150-fold solution of 90% trichlorfon crystal and then placed in the field, the cutworm larvae can be killed directly, and the efficacy can last about 7 days.

2. Poison bait trapping method: Take 1 kg of 90% trichlorfon crystal, first dissolve it in a small amount of hot water, then add 10 kg of water, and evenly spray it onto 100 kg of roasted cake powder or wheat bran. After mixing well, scatter it along the rows at the crop roots in the evening, using about 5 kg per mu. The effect of controlling cutworms is very good.

2. Sugar-vinegar liquid trapping: The preparation method of sugar-vinegar liquid is 6 parts sugar, 3 parts vinegar, 1 part white liquor, 10 parts water, and 1 part 50% diazinon, mixed evenly, and used for trapping and killing during the adult occurrence period. Some fermented and sour foods, such as sweet potatoes, carrots, rotten fruit, etc., with an appropriate amount of pesticide added, can also trap and kill adults.

4. Manual catching method: Taking advantage of the cutworm's habit of hiding by day and coming out at night, in the early morning on the ground around damaged crops, use a small iron shovel or small wooden stick to dig out cutworms and kill them.

5. Flooding method: For nurseries that can be flooded for a short period, when cutworms occur in large numbers, flood the nursery for 1-2 days, which can drown most cutworms or force them to flee, allowing manual catching and killing.

6. Black light lamp trapping: Adult cutworms have strong phototaxis. Using sugar-vinegar liquid together with a black light lamp on clear, breezy, moonless nights can achieve very good trapping and killing results. Place a basin of water under the black light lamp, add pesticide to the water, or pour in a layer of waste engine oil, which also has a good killing effect.

7. Hoeing to destroy eggs: During the peak period from cutworm egg laying to hatching, timely hoeing and cultivating can greatly reduce the egg hatching rate.

8. Grass pile trapping method: After the 3rd instar, cutworm larvae have increased pesticide resistance, and spraying pesticide on the ground is unlikely to achieve the expected effect. The grass pile method can be used for trapping, that is, in the evening evenly pile fresh grass in the field, 80-100 piles per mu, with each pile covering an area of 0.1 sq m. Early the next morning, turn over the grass piles and kill the larvae. For 5-7 consecutive days, most of the larvae can be killed. The grass piles are generally replaced every 3-4 days. After being dried by the sun, a little clean water can be sprinkled on them to improve the trapping effect.

9. Chemical control method: During the 1st-3rd instar larval stage of cutworms, use 50% diazinon emulsifiable concentrate at 2000-fold solution, 20% fenvalerate emulsifiable concentrate at 1500-fold solution, etc. for surface spraying.