Prevention and control methods of small land tiger

The generation of small land tigers, also known as soil silkworms and root cutters, varies with different climates, and more and more generations occur in the south. The occurrence is more serious in the middle and lower reaches of the Yangtze River with abundant rainfall and humid climate, and in the low-lying inland waterlogging areas along the southeast coast and north. It does great harm to farmers and forest seedlings. If it is light, it will cause the lack of seedlings and broken ridges, and if it is heavy, it will be replanted. Let's take a look at the control methods of small land tigers.

Hazard characteristics

Small land tiger is an underground pest that does great harm to the seedlings of agriculture and forests. it can harm more than 100 species of plants, such as larch, Korean pine, Manchurian ash, Juglans mandshurica and Juglans mandshurica in the northeast, and Pinus massoniana, Cunninghamia lanceolata, mulberry and tea in the south. Pinus tabulaeformis, sand jujube, fruit trees and other seedlings in the northwest. The 1st and 2nd instar larvae can cluster at the top and tender leaves of the seedlings day and night and feed day and night, when the food intake is very small and the damage is not very significant. Scattered after 3 years old, lurking between the dry and wet layers of the topsoil during the day, unearthed from the ground at night to bite off the seedlings into the soil hole, or bite the ununearthed seeds, the main stem of the seedlings hardened and changed to eat tender leaves, leaves and growth points. The food intake of the 5th and 6th instar larvae increased greatly, and each larva could bite off 4-5 plants of vegetable seedlings in one night, and more than 10 plants.

Occurrence regularity

Small land tigers have seen occurrence and harm from October to April of the second year, two to three generations in the northwest, two to three generations north of the Great Wall, three generations a year to the north of the Yellow River to the south of the Great Wall, four generations a year from the south of the Yellow River to the banks of the Yangtze River, four to five generations a year to the south of the Yangtze River, and six to seven generations a year in the south of the Yangtze River. No matter how much algebra occurs every year, it is the first generation larvae that cause serious harm in production. The adults of the overwintering generation in southern China appeared in February, and the peak period of Eclosion was from late March to early and mid-April in most parts of the country, and late April in Ningxia and Inner Mongolia. The fecundity and egg period of adults are different in different places, and the main reason for the difference of egg period with distribution area and generation is the difference of temperature.

Agricultural prevention and control

1. Strengthening management: extensive management and overgrowth of weeds are the best hosts to induce ground tiger to spawn and feed in advance. The more weeds are, the higher the survival rate of larvae is and the more serious the harm is.

2. Make use of natural enemies, such as Raven Finch, Toad, Weasel, Walker, parasitic fly, parasitic wasp, bacteria, Fungi and so on. The parasitism rate of parasitoids and cocoon wasps in Hangzhou is 10%.

3. Adult trapping: trapping and killing adults with sugar, vinegar, wine or fermentation broth such as sweet potato and carrot.

4. Larval trapping: trapping larvae with paulownia leaves or lettuce leaves and catching them in the field every morning. The older larvae can also be inspected in the field in the early morning. If broken seedlings are found, the nearby soil clods can be plucked and killed.

Chemical control

Different spraying methods should be used for different instar larvae. Before the 3rd instar, the larvae were controlled by spraying, spraying powder or spreading poisonous soil, and the seedlings were broken in the field after the 3rd instar, which could be killed by poison bait or poisonous weeds.

1. Spray control: 50% phoxim EC 750 ml per hectare, or 2.5% deltamethrin EC or 40% cypermethrin EC 300g 450 ml, 90% crystal trichlorfon 750g, 750L spray on water. The appropriate period of spraying should be before the 3rd instar of the insect.

2. Poisonous soil control: choose 2.5% deltamethrin EC 90ml 100ml, or 50% phoxim EC or 40% methyl isophos EC 500ml with appropriate amount of water, spray 50kg of fine soil to form poisonous soil, 300kg / ha and 375kg per hectare spread along the ridge near the seedling root mark.

3. Poison bait control: generally, poison bait can be used for older worms. 0.5 kg of 90% crystal trichlorfon or 500 ml of 50% phoxim EC can be selected, 2.5 kg of water is added, and sprayed on 50 kg of crushed cottonseed cake, bean cake or wheat bran, sprinkle a small pile at a certain distance in the field of damaged crops in the evening, or surround the crop rhizosphere with 75 kg per hectare.

4. Prevention and control of poisonous weeds: 0.5 kg of 90% crystal trichlorfon, 75 kg of smashed fresh grass, 225 kg and 300 kg per hectare.