Control of species of litchi bugs

Litchi bugs, belonging to Hemiptera and Pentatomidae, is a major pest of longan in our region. The insect sucks the juices of tender shoots, flower ears and young fruits with adults and nymphs, and the damaged parts change color and dry up, resulting in falling flowers and fruits. When the insect is frightened, the smelly liquid touches the tender leaves, flowers and fruits, which can cause burns and scorch, and the fruit shell becomes scorched brown, which seriously affects the yield of longan.

Litchi bugs produce one generation a year, overwintering with sexually immature adults on the back of leaves or tree holes and stone gaps in sheltered, sunny or dense foliage. In the following spring, when the temperature reached about 16 ℃, they began to move and like to gather on trees with luxuriant flowers and leaves to feed. April was the peak period for mating and spawning. Most of the eggs are laid on the back of the leaves under the crown, and each female can lay eggs 5 times per female for 10 times, up to 17 times. Most of them lay 14 eggs each time, gathered and arranged into blocks. After Qingming Festival, nymphs hatch one after another, pricking and sucking the juices of tender shoots, spikes and young fruits, often causing flowers and fruits to fall. After 6 months, mature nymphs become adults one after another, and adults like to eat tender shoots and fruit ears.

The appropriate period of prevention and treatment is the most important in two periods. First, when the overwintering adults begin to be active in early spring, that is, in the middle and late March, the adults are about to lay eggs, and the drug resistance is the weakest, and at this time, killing adults with drugs can significantly reduce the population base, which is very beneficial to the control of the whole year. Use 90% crystal trichlorfon 500 murmur800 times or mifenlingling EC 1500 murmur2000 times, or pyrethroid pesticides (such as Xingmianbao, Quick killing the enemy, Mianbaike, etc.) 1500 muri 2000 times to prevent and cure 1 Mutual for 2 times.

Another suitable period for control is in mid-late May, when the eggs have hatched in a large number of nymphs. 1 the body surface of the 2nd instar nymphs is thin in wax, low in keratinization and sensitive to drugs. A better control effect can be achieved by adding 5000 times of 20% fenvalerate plus 1000 times of 40% omethoate or 4.5% cypermethrin 2500 times of cypermethrin.

It is appropriate to take medicine in the morning or evening when there is no dew, when the temperature is lower, the false death of the bugs is more obvious, the activity is weak, and it is easy to come into contact with drugs. Conditional orchards can manually remove egg blocks and exterminate nymphs from March to May. It can also release flat-bellied wasps and litchi bugs to parasitize the eggs of litchi bugs. Check the tree bugs density once before releasing the bees in mid-late March. Each plant has 150 bugs and can release more than 150 bees. Spraying trichlorfon once to depress the adult density, and then releasing the second batch of bees 5 days later can reduce the harm of overwintering old adults.