Prevention and Control of Potato damage caused by Bean Daphne

At present, it was found to be harmful to plastic film potato in Longhu District, Shizuishan City, covering an area of about 30 mu. The leaves of individual fields were seriously damaged, affecting the normal growth of potatoes.

There are three kinds of beetles, namely, EpicautagorhamiMarseul, MylabrisciohoriiLinne and MylabrisphalerataPallas, which are widely distributed in China. It is mainly harmful to legumes, peanuts and peppers, as well as tomatoes, potatoes, eggplant, sugar beet, water spinach, amaranth and other crops. Take the adult as the harm, mainly feed on the leaves and petals, eat the bean leaves, leaving only the veins, and also eat the pods, which affect the yield and quality.

1. Morphological characteristics

All of them belong to Coleoptera, Daphne. The adult of bean white stripe is 15-18 mm long and dark brown. The head is slightly triangular and reddish brown. There is a vertical yellow-and-white stripe on the center of the anterior chest dorsal plate and on each of the two sheath wings. The eggs are oval, yellow and white, and the egg blocks are arranged in the shape of a chrysanthemum. The larvae of the 1st instar are dark brown trichophyta with active movement, the 2nd-4th instar and 6th instar are glossy type, and the 5th instar is a pseudopodium without feet. The naked pupa is about 15 mm long, yellowish-white, with 9 long thorns on the lateral and posterior edges of the anterior thoracic dorsal plate. The adult body of Daphne genkwa is about 15 mm long, and there are significant longitudinal seams in the dorsal plate of the forechest. The sheath wings are yellow except for three wavy transverse bands that are black, so there are yellow and black flowers on the sheath wings. Large yellow-black flower beetle, the shape of the adult is similar to that of yellow-black flower, and the sheath wing also shows yellow-black flowers, but it is larger, 20-28 mm long, and the longitudinal seam of the forechest dorsal plate is not obvious.

II. Living habits

Bean beetle occurs one generation a year in Northeast and North China, and two generations a year in the Yangtze River Basin and the provinces south of the Yangtze River Basin. The 5th instar larvae (false pupae) overwintered in the soil. In the first generation area, the overwintering larvae pupated in mid-June, the adults appeared from late June to mid-August, and August was the serious damage period. The overwintering adults occurred in the second generation area from May to June, focusing on early sowing soybean and then turning to vegetables. The first generation of adults were the most harmful to soybeans, and then the number decreased gradually and transferred to vegetables. Adults are active during the day, cluster on the branches and leaves of bean plants, and are lively and good at crawling. When frightened, the adult spreads or falls to the ground quickly, and can secrete yellow liquid containing genkwanin from the end of the leg, which can cause redness, swelling and foaming if it touches human skin. Adults lay eggs at a depth of about 5 cm in the soil, with about 70,150 eggs in each hole.

III. Comprehensive prevention and control methods

The main results are as follows: (1) Deep ploughing of the soil in winter can make the overwintering pupae freeze to death or be eaten by natural enemies, and reduce the number of insect sources in the following year.

(2) artificial hunting and killing the habit of making use of adult clusters, catching and killing with nets, but should be careful not to touch the skin.

(3) in the initial stage of adult occurrence, some adults are artificially captured and strung into several strings with iron thread and hung around legume crops in the field, which can avoid the damage caused by adults.

(4) 1000-fold liquid spray of 90% trichlorfon crystal was selected for chemical control during the occurrence of adults.