Peanut pests and diseases

Bacterial wilt

It can occur from the seedling stage to the harvest stage, and the disease is most serious in the flowering stage.

The typical symptom is that the disease will recover sooner or later during the day, and it will not recover sooner or later. The leaves of the diseased plants sagged from top to bottom, and the leaves were dull, but still blue-green.

The roots of the diseased plants will become brown and rot, and the stems of the stems will be brown. When squeezed by hand, there will be stained white pus.

Chemical control:

In the early stage of the disease, it is controlled by chloramphenicol or trichloroisocyanuric acid.

2. Peanut black spot

It mainly occurs in the middle and late stages of peanut growth. It mainly harms the leaves and can also damage the petiole and stem.

The lesions are round and dark brown, small, sometimes with a yellow halo, and the lesions on both sides of the leaf are basically the same. When wet, gray-brown mold is produced on the lesion.

The lesions on the petiole and stalk are elliptical, dark brown, and the lesions are often irregularly large, and the entire petiole or stem becomes dark and dead.

Control agents:

It can be controlled by azole ether, dexamethasone, tebuconazole, mancozeb, benzoyl bromide and the like.

3. Peanut brown spot

Growing in the middle and late stages. Mainly harmful to the leaves, can also be harmful to the petiole and stalk.

It starts with a small spot that fades green and then expands into a small round spot.

The lesion is larger and lighter than black spot. The front of the leaves is dark brown or brown, with a bright yellow halo around the lesions. When the humidity is high, there will be a grayish brown powdery layer. If the disease is serious, the lesions will converge and the leaves will dry out.

Control agents:

It can be controlled by azole ether, dexamethasone, tebuconazole, mancozeb, benzoyl bromide and the like.

4. Peanut net blotch

It usually starts from the flowering down needle stage, and the onset period is from the pod-forming stage to the maturity stage. It mainly harms the leaves and also damages the petiole and stem.

The lower leaves of the plants are firstly damaged, producing brown dots or star-shaped nets on the front of the leaves.

After the lesion is enlarged, it forms a nearly round brown to dark brown spot, the edge is unclear, the surface is rough, the coloration is uneven, and there is no yellow halo.

Chemicals:

In the early stage of the disease, thiophanate-methyl + hexaconazole, mancozeb, poly-manganese-zinc or difenoconazole was used for prevention and treatment.

5. Peanut focal spot disease

It mainly begins at the beginning of flowering. It mainly harms the leaves and also harms the petiole, stem and fruit stalk. The lesions on the leaves occur mostly at the tip or leaf margin and can also occur inside the blade.

The lesions at the edge of the tip are often semi-circular, the lesions are browned from yellow, and the edges are yellow halo. In the later stage, the plaque becomes grayish brown and will rupture.

Chemicals:

In the early stage of the field, it is possible to control the drugs such as trichloroisocyanuric acid, carbendazim, and chlorothalonil. The spray is sprayed once every 10 to 5 days, and the disease is sprayed 2 to 3 times. In severe cases, it can be controlled with difenoconazole or benzazole.

6. Anthrax

Mainly harmful to the leaves, the following parts of the leaves more. The lesion spreads along the main vein, brown or dark brown, and is wedge-shaped, oblong, or irregular.

There are no obvious wheel marks on the lesions, the edges are yellowish brown, and many small black spots are not obvious on the lesions.

Chemical control:

In combination with other leaf spot diseases and early spraying, optional bromoxynil, flusilazole or difenoconazole can be sprayed 2 to 3 times, once every 7 to 15 days.

7. Stem rot

It can be sick from the seedling stage to the maturity stage. It mainly harms the base, root and stem of the stem of peanut.

Spread to the base of the stem, the base of the stem becomes dark brown and rot, and the leaves of the diseased plant turn yellow, wilting and drooping, and soon die.

The adult stage jeopardizes the base of the main stem and side branches, producing yellow-brown water-stained spots, and the posterior lesions expand downward, causing the roots and stems to become black and dead.

Control agents:

Seed treatment: seed dressing with carbendazim and methyl thiophanate. Then, carbendazim or thiophanate-methyl is sprayed once after the peanut seedlings and before and after flowering.

8. Root rot

It can occur in all growth stages of peanuts. In the adult stage, the upper part of the diseased plant showed short stature, poor growth, yellowing of the leaves, and eventually the whole plant withered.

Because the disease is mainly in the roots and vascular bundles, the roots of the diseased plants become brown and rot, and the vascular bundles become brown.

The main root shrinks and rots, and looks like a rat tail.

Control method:

Before sowing, it can be used for seed dressing with fludioxonil and difenoconazole, which can effectively prevent the occurrence of root rot before, and has a long effective period and good effect.

In the early stage of the disease, timely spraying or rooting of the drug may be carried out by using a fluopyram or a flavonoid. Spray once every 7 days and spray continuously for 2 to 3 times. It can effectively prevent root rot and spread to the surrounding area.

9. White sickness

After the peanut roots, pods and stem bases are damaged, they are often brownish soft and rotted, and the ground rhizomes have white scorpion hyphae.

When the humidity is high, the white silky hyphae can be covered to cover the diseased part and the surrounding ground, and then the rapeseed-like white small sclerotium is produced, and finally the yellowish color is dark brown.

Chemical control:

Seed treatment before sowing: seed dressing with carbendazim. In the lower needle period of peanut, the following agents can be sprayed once every 7 to 10 days with procymidone and iprodione for 3 to 4 times. Or spray triazolone, iprodione or other agents at the beginning of pod formation.

10. Rust

It can occur at various stages of growth, but it occurs severely after the pod-forming period. Mainly infested with peanut leaves, it can also damage petiole, stipules, stems, fruit stalks and pods.

At the beginning of the leaf infection, a pale yellow lesion with a needle tip size appeared on the front or back of the leaf, and then expanded into a pale red protruding spot, and the epidermis ruptured to reveal a reddish brown powder.

Chemical control:

In the early stage of the disease, it was sprayed with powder rust, diniconazole, propiconazole, and prochloraz.

11. Viral disease

Diseases occur throughout the reproductive period.

Peanut virus disease often has the following types:

Peanut Stripe Virus Disease:

The leaves of the top leaves of the plants were dark and faint, and the green veins along the lateral veins showed that the plants were slightly dwarfed and the leaves were not significantly smaller.

Peanut yellow mosaic virus disease:

At the beginning of the plant, the young leaves are chlorotic yellow spots, and the leaves are curled. Then they develop yellow-green interflowered leaves, reticular veins and other symptoms. The diseased plants are moderately dwarfed.

Peanut dwarf virus disease:

At the beginning of the young leaves, there are bright veins or chlorotic spots, and then develop into common green leaf symptoms of light green and green. Radial green stripes and spots along the lateral veins, the leaves become narrow and small, and the leaf margins are wavy and twisted. The strain is often moderately dwarfed.

The pods are obviously blocked and form many small fruits and deformed fruits.

Chemical control:

In the early stage of the disease, drugs such as trichloroisocyanuric acid or amino oligosaccharide, strontium acetate, copper acetate, and lentinan can be used for 5 to 7 days, and used for 2 to 3 times. Timely trapping or killing poisonous insects (field mites) spraying imidacloprid, acetamiprid and other agents.

12. Root knot nematode

It is mainly caused by the lower part of the plant, causing the growth of the aboveground part.

Any part of the peanuts (roots, pods, etc.) can be harmed by nematodes.

The nematode invades the roots, causing the apex to expand into a spindle-shaped or irregular root knot, initially milky white, then pale yellow to dark brown, and the surface is rough. In addition, root knots can sometimes be formed on the root neck, the stalk and the husk.

note:

The root-knot nematode we are talking about here is different from the root nodule of peanut. The root-knot nematode insect is often born at the tip of the root, so that the root end is swollen into a spindle-shaped or irregular shape, the surface is rough, and many fibrous roots are grown. There are milky white sand-like females. The nodule with nitrogen fixation is often born on one side of the main and lateral roots, round or elliptical. The size of the soybean is relatively uniform, the surface is smooth, and no roots are required.

Chemical control:

Pre-sow treatment: Use thiazolyl, avermectin, or avid thiazolyl to ditch evenly and then cover the soil.

13. 蛴螬

Peanut flowering can be harmful in the lower needle stage, pod stage and full fruit ripening stage.

Adults (chafers) bite on the leaves and bite into irregular nicks or holes. In severe cases, only the veins remain.

The larvae bite the roots and stems of peanuts, causing peanuts to lack seedlings and ridges, and biting peanuts seriously. Will eat all the tender fruit, bite the old fruit into an empty shell.

Control method:

When the peanuts are harvested, the cockroaches that are turned out are collected and destroyed at the same time as the peanuts are harvested, which can effectively reduce the density of the larvae in the coming year.

Soil treatment. Mainly with chlorpyrifos, phoxim granules mixed with fine soil applied to the seeding ditch or seeding hole, has a certain effect.

14. Peanut aphids

From late May to late June, it is the main hazard period and needs to be controlled.

The nymphs clustered in the young leaves and buds of peanuts, causing the leaves to turn yellow and curl, grow slowly or stop, and plant dwarfs affect flower bud formation and pod development.

Control agents:

Peanut growth period mainly uses imidacloprid, acetamiprid, avermectin and other agents to spray water. Spray the nozzle up, spray the back of the leaf, and pay attention to spray.

15. Helicoverpa armigera

The main occurrence period is from late June to early July.

The younger larvae can sew the unopened young leaves and feed on the mesophyll, leaving only the leaves of the leaves to form a transparent shape.

After 3 years of age, the leaves are eaten, and the leaves can be eaten into nicks or holes.

Chemical control:

Peanut flowering and needle down period is the best period for drug control. The medicament can be sprayed and controlled by avermectin, beta-cypermethrin, emamectin benzoate, hexaflumuron and the like.

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