1, peanut black spot disease: mainly occurs in the growth of peanuts in the middle and late, harming the leaves, but also can harm the petiole and stalks, spot round dark brown, smaller, sometimes there will be a yellow halo. 2, peanut brown spot disease: the growth of the middle and late, mainly harming the leaves, but also can harm the petiole and stalks, the beginning of the green spot, and then expand into a nearly round spot. 3, peanut net spot disease

A peanut black spot disease

1, symptoms

(1) peanut black spot disease generally occurs in the growth of peanuts in the late stages, the main harm to the leaves, and sometimes also harm the petiole and stalks.

(2) The spots are round and dark brown, small, sometimes with a yellow halo, the leaf blade is basically the same on both sides of the spot, when wet, the spot will produce gray-brown mold.

(3) petioles and stalks on the spot is oval, black-brown, more spots will be connected to the irregular large spots, when serious, the whole petiole or stalks will turn black and die.

2, control agents

can use azoxystrobin, tebuconazole, penconazole and other chemicals to prevent and control the disease. Diclofenac, tebuconazole, diclofenac manganese-zinc, benomyl, bromoxynil and other agents. Bromoxynil and other agents for control.

Second, the peanut brown spot disease

1, symptoms

(1) peanut brown spot disease is generally easy to develop in the growth of the late, can harm both the leaves, but also can harm the petiole and stalks.

(2) The early stage of the disease is a small green spot, gradually expanding into a nearly round spot, the spot is larger and lighter in color than the black spot disease.

(3) The leaf blade is dark brown or tea brown on the front, there is a bright yellow halo around the spot, gray-brown powdery mold will appear when the humidity is high, and when the disease is severe, the spots will converge and make the leaf blade dry and fall off.

2, control agents

can use azoxystrobin, tebuconazole, tebuconazole and other chemicals to prevent and control the disease. Diclofenac, tebuconazole, diclofenac manganese zinc, benzothiophene, bromoxynil and other agents can be used to control the disease. Bromoxynil and other agents to control.

Third, peanut web spot disease

1, symptoms

(1) peanut web spot disease is generally infected from the flowering of the next needle period, the onset of the peak period is mainly in the pods to the maturity period.

(2) the disease will harm the leaves, petioles and stems, the lower leaves of the plant is first victimized, in the front of the leaf produced brown dots or stellate reticulation.

(3) The disease spot will form a nearly round brown to black brown spots after expanding, the edge of the reticulation is not clear, the surface is relatively rough, the coloring is not uniform, no yellow halo.

2, chemical agents

The early onset of the disease can use thiophanate-methyl + hexaconazole, diclofenac manganese zinc, more? Manganese zinc or phenyl ether metronidazole and other agents to control.

Fourth, peanut scorch disease

1, symptoms

(1) peanut scorch disease mainly in the beginning of the flowering period began to develop, usually harm the leaves, petioles, stems and petioles, leaf spots on the leaf tip or leaf margins, but also in the inner leaf.

(2) The spots at the edge of the leaf tip are often semi-circular, the spots turn from yellow to brown, ? There is a yellow halo around the edge, and the spots will turn gray-brown and die and break at a later stage.

2, chemical agents

In the early stage of the disease, you can use trichloroisocyanuric acid, carbendazim, chlorothalonil and other agents to control the disease, every 10-5 days or so, spray 1 time, the disease can be sprayed 2-3 times, and when it is serious, you can use phenyl ether metacyclonazole or benzothiazole? propiconazole for spray control.

V. Grubs

1, Symptoms

(1) grubs are generally in the peanut flowering under the needle period, podding and full fruit ripening period of damage. Adult grubs (golden turtles) will bite the leaves, the leaves into irregular gaps or holes, and in severe cases only the leaf veins remain.

(2) grub larvae will bite the peanut roots, stems, so that the peanut lack of seedlings broken, and in severe cases will bite the peanut fruit, the young fruit all eaten up, the old fruit bite into the empty shell.

2, prevention and control methods

(1) when harvesting peanuts must be turned out of the grubs collected and centralized destruction, which can effectively reduce the density of the next year's population.

(2) the use of chlorpyrifos, phoxim and other granules mixed with fine soil applied to the seeding ditch or seeding hole, so there is also a certain degree of prevention.

Six, peanut aphids

1, symptoms

(1) late May to late June is the main period of damage, be sure to focus on prevention and control.

(2) adults and wakame will cluster in the peanut young leaves, shoots and other parts, resulting in yellowing and curling of the leaves, slow growth or stop, plant dwarfing affect the formation of flower buds and pod development.

2, prevention and control agents

In the peanut growth period you can use imidacloprid, amidacloprid, abamectin and other agents in water for spraying, spraying nozzle must be facing up, you can spray the back of the leaf.