Two spotted spider mite (Tetranychus urticae Koch) is an arachnid, subfamily, aphid, and leafhopper, also known as two-spotted spider mite, white spider. Tetranychus urticae is a kind of pest that spreads almost all over the world. According to studies of Dong Huifang and other institutes of the Chinese Academy of Agricultural Sciences, before the 1980s, there was no distribution of this species in China. Many records in the past were erroneous. The two-spotted spider mite may have been introduced into China with foreign flowers, fruit tree seedlings, and strawberry seedlings in the mid-1980s. The cricket host is extensive and can serve as the host of the cinnabar. In addition, it also harms apples and pears.
Hazardous characteristics: The two-leafhopper sucks juice on the back of the leaves with a sucking mouthpart, resulting in the appearance of small white chlorotic spots on the leaves. When severely damaged, the leaves are in a coke-like form, with a layer on the front or branches of the leaves. White silky silk screen?
Morphological characteristics
Females become female: 0.42 to 0.59 mm in length, oval, with 26 bristles on the back of the body, arranged in 6 rows. The growing season is white, yellowish-white, with one black long spot on each side of the back of the body and dark green and brown green after feeding; when the density is high, or the body color turns orange before the migration. No red individual appears during the growing season. Diapause-type body pale red, body side without spots. The biggest difference from the cinnabarin is that there are no red individuals in the growing season and the others are the same.
Xiong Chenghao: The body length 0.26 mm, nearly ovoid, the front is nearly round, the abdomen is more pointed, mostly green. It is indistinguishable from cinnabar.
Eggs: Spherical, 0.13 mm long, smooth, first milky white, yellow-orange, will appear red eyes when hatching.
Cubs: Nearly round when newly hatched, body length 0.15 mm, white, dark green after feeding, red eyes, 3 pairs of feet.
If 螨 螨 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? å‰ å‰ å‰ èž¨ 螨 螨 螨 螨 body length 0.21 mm, nearly ovoid, feet 4 pairs, deep color, body spots appear back. If the body is 0.36 millimeters long, it is similar to that of Chengyu.
Occurrence characteristics: Two-spotted spider mites occur more than 20 generations in the south and 12 to 15 generations in the north. In the north, fertilized female adults in the rhizosphere, such as earth seams, litters, or perennial root weeds, etc. at the rhizosphere of weeds in the rhizosphere. On trees, wintering occurs under the bark, in cracks or in the soil at the neck. When the average temperature in March reaches around 10°C, the overwintering females begin to eel and spawn. Overwintering females are mostly concentrated in the early spring host such as small bindweed, grass, asteraceae, cruciferous and other weeds and vegetables on the damage, the first generation of eggs also produced these weeds, the egg period more than 10 days. It takes 20 to 30 days for adults to lay eggs until the first generation larvae hatch. In the early spring, a generation usually occurs on the host, and after the beginning of May, they migrate to vegetables and harm them. Due to the low temperature, May will not cause major damage. As the temperature rises, its reproduction speeds up, and it enters the annual hazy incursion period in the middle and early June. It enters the mid-to-middle peak period in mid-July. According to the author's research, the occurrence period of the two-spotted spider mites is longer, and the general year can be maintained until around mid-August. Diapause individuals have appeared one after another in October, but when the temperature exceeds 25°C, diapause individuals can still resume feeding, and their body color changes from diapausing red to yellow-green, and they enter diapause for winter after entering November. Two-spotted spider mites reproduce sexually, fertilized eggs develop into females, and no sperms develop into males. Each female can produce 50 to 110 eggs and can lay up to 216 eggs. Happily clustering leaves near the main veins and spinning silk nets under the net damage, when the large occurrence or food shortage, often more than a thousand head clustered in the leaf ends into a swarm. The duration of development is not the same for different host hosts. For example, leaves of peanuts take 11.04 days and 7.96 days at 25°C and 30°C, and 11.48 days and 8.63 days for apple leaves. The host difference has the greatest influence on the fecundity of female adults. According to the authors' study, under the condition of peanut leaf feeding at 30°C, the average female lays 56 eggs, but under the same conditions, feeding apple leaves, the amount of eggs laid is only 29 capsules.
Once introduced, it will replace other pests and become a dominant species in local vegetables, crops, and fruit trees.
Prevention and control methods? In the prevention and control, comprehensive prevention and control strategies shall be adopted that combine agricultural control, biological control, and chemical prevention. Because this cockroach has a very high resistance to drugs, it should be mastered in the initial stage of prevention and control, and once it is severe it is difficult to control.
1. Agricultural control? In the early spring and late autumn, clean the pastoral area. After mid-April and late April, when the population of Tetranychus urticae on the weeds is mainly eggs and young larvae, the weeds in and around the fruit field are promptly removed and the worms on the weeds are eliminated, and migration to the tree body can be reduced. The number of crickets delays the occurrence of the occurrence and peak periods of the mid-year, and shortens the duration of the cricket.
2. Chemical prevention and control: The effective agents for the control of the two-spotted spider mite are: 1.8% abamectin EC 3000 times, 15% Liuyangmycin EC 1500 times, 15% triazotin (BEILER) suspension agent 1200 Times liquid, 5% baclofen (azopyrazole ester) suspension 2000 times, 15% fluorenone emulsion 2000 times, 10% dichlorination (chlorinated nitrile) 3000 times, 2% Russell hair Chrysanthemum) 2000 times solution of emulsifiable concentrate, 20% exfoliate (fenpropathrin) 1200 times solution of emulsifiable concentrate, 10% solution of emulsifiable concentrate and 3000 times solution of emulsified (quinoxaline) emulsifiable concentrate. In order to increase the insecticidal effect, a synergist such as 10% Lipo-Ping 1000 times liquid may be added to the liquid, and the spray should be used for spraying in case of occurrence.
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