Occurrence and control of rice water weevil

Rice water weevil is an international agricultural plant quarantine pest, which first occurred in America and in Asia, such as Japan, South Korea, North Korea and so on. The rice water weevil was first found in China in 1987 in Tanghai County, Hebei Province.

The rice water weevil was first found in Ji'an City, Tonghua District in August 1993. At present, this kind of pest occurs to varying degrees in most areas of Heilongjiang Province.

I. the damage degree of rice water weevil

Rice water weevil mainly harms rice and some Gramineae plants. The adults and larvae of rice water weevil are harmful to rice. The adults feed on the leaves of young rice and leave their epidermis. The larvae ate the roots and ate in and on the rice roots. The 1st and 3rd instar larvae ate the roots, and after the 4th instar, they climbed out of the rice roots and ate the roots. The roots blackened or rotted after being eaten, and the windy rice plants were easy to lodge. The yield of plots with insect pests is generally reduced by 20%, and the yield of fields with heavy rice water weevil can be reduced by up to 50% and 70%.

Second, the living habits of rice water weevil

Rice water weevil is a semi-aquatic insect. The insect can be divided into two types: bisexual reproduction and unisexual reproduction (adults can parthenogenesis). All the rice water weevil occurred in China are parthenogenetic. Adults overwinter in rice straw, rice stubble, Gramineae weeds around paddy fields and ridges of fields. The overwintering adults begin to recover when the temperature reaches about 10 ℃ in spring. After recovery, we first eat the new leaves of Gramineae crops, and then enter the rice field to do harm after rice transplanting.

3. Characteristics of rice water weevil

The pest has strong stress resistance, hunger tolerance, low temperature tolerance, high reproduction rate (50-75 eggs per adult) and wide parasitism.

Rice water weevil spreads fast. This pest can crawl, fly and swim. It can be spread by current, airflow and means of transportation.

4. Control methods of rice water weevil

The introduction of rice water weevil into the area where rice water weevil has not occurred should be controlled. Should act in strict accordance with plant quarantine regulations. Do not introduce varieties from epidemic areas, and do not transfer rice straw and straw products from epidemic areas or occurrence areas.

Prevention and control measures in occurrence areas:

1. Rational fertilization. In order to achieve soil testing and fertilization, we can make up for what is missing. Too much nitrogen fertilizer can easily increase the population density.

2. Remove weeds. In autumn, winter and spring, the weeds around the rice fields should be cleared or burned so that they can lose their overwintering places and directly eliminate pests.

3. In view of the phototaxis of the adult rice water weevil, a black light can be set up near the rice field to trap and kill.

4. Chemical control. At present, the chemical agents with better control effect on rice water weevil have been screened out, such as Dao Lefeng, Wei Dao EC, Weishujing, Shachongshuang and so on.

In the prevention and control methods, we should take the village as a unit to carry out joint prevention and control, and achieve the "four unity". That is, unified organization, unified drug purchase, unified time administration, unified inspection. This is beneficial to improve the control effect. The time of prevention and control should be carried out according to the actual local conditions. The overwintering adults are generally controlled from June 5 to 10, and the new generation adults are controlled at the beginning of August.