How to prevent and control plant powdery mildew? What are the specific effective drugs?

Powdery mildew mainly damages the leaves of crops, and also damages stems and ears. It can occur from the seedling stage to the heading stage. Yellow small spots first appear on the leaves, then expand into round or oval lesions, with a white powdery mold layer on the surface. It is caused by Blumeria graminis and mainly damages wheat, barley, rye, oats, etc. Now let us take a look at what specific effective drugs there are for powdery mildew!

Specific effective drugs for cucumber powdery mildew

During the disease period, use 50 grams per mu of Kongbai wettable powder, or use 5% chlorothalonil dust or sublimed sulfur powder for dusting. In particular, it should be mentioned that spraying with a 0.1-0.2% baking soda solution has a good control effect. Baking soda is a weakly alkaline substance and can inhibit the growth and spread of many fungi. After spraying, it can decompose into water and carbon dioxide, and also helps promote photosynthesis. It is also cheap, safe, and pollution-free.

Specific effective drugs for rose powdery mildew

Before bud break, spray 5 lime sulfur mixture. In the early stage of the disease, spray 25% triadimefon wettable powder at 1500 times dilution, or spray 70% thiophanate-methyl wettable powder at 1000 times dilution, or spray 15% triadimefon wettable powder at 1000 times dilution, or spray 0.02-0.03% potassium permanganate solution.

Specific effective drugs for melon powdery mildew

1. Add 15 kg of water to every 20-30 ml of ethirimol and kresoxim-methyl upgraded precise compound formula (Kongbai). Spray once every 7 days, 2-3 sprays in total. This drug is used in plots where powdery mildew occurs alone or where downy mildew also occurs mildly at the same time. Note that when mixing the drug, it must not be mixed with any other pesticides or chemical fertilizers. Use clean water to mix the drug. Canal water must be settled before it can be used to mix the drug.

2. Spray 80% sulfur at 400 times dilution plus 72% benziothiazolinone and cymoxanil at 600 times dilution. Mix 150 grams of sulfur plus 100 grams of benziothiazolinone and cymoxanil with 60 kg of water. Triazole fungicides such as myclobutanil or triflumizole can also be used.

Specific effective drugs for grape powdery mildew

1. Before grape buds swell but before they sprout, spray 3-5 degrees Baume lime sulfur mixture or 45% crystalline lime sulfur mixture at 40-50 times dilution. Starting in June, spray Bordeaux mixture once every 15 days, spraying 2-3 times continuously for prevention.

2. Spray drugs for control in the early stage of the disease: 300 million CFU/g Trichoderma harzianum wettable powder at 300 times dilution, 10% flusilazole at 1500 times dilution, 70% thiophanate-methyl wettable powder at 1000 times dilution, ethirimol Kongbai at 800 times dilution, 40% carbendazim · sulfur suspension concentrate at 600 times dilution, 50% sulfur suspension concentrate at 200-300 times dilution, kresoxim-methyl Kongbai at 8000-1000 times dilution, 200/0 triadimefon sulfur triadimefon · sulfur suspension concentrate at 2000 times dilution, 56% azoxystrobin and chlorothalonil at 600 times dilution.

Specific effective drugs for wheat powdery mildew

1. Spray drugs for control in the early stage of the disease in spring. Select 80-100 grams per mu of 15% triadimefon wettable powder or 20-30 grams of 12.5% diniconazole wettable powder, add 80-100 grams of monopotassium phosphate or 50 grams of chitosan, mix evenly, then add 30-45 kg of water and spray evenly. Generally spray 1-2 times, which can achieve the goals of drought resistance, disease prevention, preventing dry hot wind, and improving plant stress resistance.

2. In the wheat jointing stage, spray 30 kg per mu of 200 micrograms/ml paclobutrazol solution, which can dwarf the plants, enhance lodging resistance, and also control wheat powdery mildew, improving the plant's absorption and utilization rate of nitrogen.

3. When the diseased plant rate reaches 15-30% or the diseased leaf rate reaches 8-15% at the booting and heading stages of wheat, use 50 grams per mu of 15% triadimefon wettable powder or 40 grams per mu of 20% triadimefon emulsifiable concentrate, add 10 kg of water, and spray. Generally one control treatment can control the disease.

April garden plant pest and disease control

    I. April leaf-eating pests:

(1) Box tree pyralid: It enters the peak damage period in late April. In severe cases, the leaves are eaten completely and the whole plant turns yellow and withered. In the early stage, 2500 times diluted diflubenzuron can be used. For older larvae, 1000 times diluted 40% omethoate emulsifiable concentrate can be used for control.

(2) Scarab beetles: Adults can be shaken from trees and killed in a concentrated way by taking advantage of their feigning death, or trapped with black light lamps.

(3) Fall webworm: In mid-April, overwintering-generation fall webworm adults emerge. They can be caught manually for control.

(4) Sophora japonica looper: In late April, the first-generation larvae of the Sophora japonica looper begin to cause damage. The best period should be seized to spray diflubenzuron and other agents.

II. April trunk-boring pests:

In April, trunk-boring pests begin harmful activity. The main ones include rusty longhorn beetle, glossy longhorn beetle, and Ailanthus weevil. In addition to manual injection of chemicals, control should be carried out according to the habits of different pests.

III. April piercing-sucking pests:

1. Aphids. The aphids that should be focused on for control include: green peach aphid, rose long-tube aphid, willow black hairy aphid, Koelreuteria aphid, cotton aphid, etc. The preferred agent for controlling aphids is the biological insecticide 1.2% nicotine and sophocarpine emulsion at 800-1000 times dilution. Other options include 40% omethoate emulsifiable concentrate at 1000 times dilution, imidacloprid at 2000 times dilution, etc. Note that organophosphorus insecticides should be used with caution on peach trees and other Rosaceae plants to prevent phytotoxicity.

2. Scale insects. Giant mealybugs, peach scale insects, etc. begin activity and cause damage. Control methods mainly include applying poisonous rings, and some specific scale-killing drugs can also be selected for control.

3. Spotted lanternfly. Hatching begins in late April. Groups of small nymphs gather on tender branches to cause damage. The favorable opportunity should be seized for control. Pyrethroid insecticides at 1000 times dilution can be used.

4. Spider mites. From late April to early May, the first-generation nymph mites cause damage, spinning silk and forming webs. A layer of gray sticks to cypress leaves, and the needles turn gray and yellow, seriously affecting the ornamental effect. During detection, shake a small branch several times in the palm. If black small dots are found crawling, it indicates mite occurrence, and drugs should be sprayed promptly for control. Drug choices include 15% pyridaben at 1500 times dilution, fenpyroximate at 2000 times dilution, and 20% dicofol at 1000 times dilution.

IV. April underground pests:

Attention should be paid to controlling white grubs. 1000 times diluted 50% phoxim emulsifiable concentrate can be used for spraying and watering.

V. April diseases:

This month, some diseases are in the initial infection stage, such as Euonymus japonicus powdery mildew and rose black spot. Prevention should be the main approach. The key control target in this period is canker disease of various tree species. The main control methods are strengthening fertilizer and water management and applying chemical agents.

Symptoms and control methods of 9 major pests and diseases of succulents

Illustrated symptoms and control methods of 9 major pests and diseases of succulents

Autumn has arrived, and it is once again a good season for growing succulents. But succulents often suffer from some pests and diseases, and many flower lovers are anxious and do not know how to deal with them. Today Huahua will show you picture-based diagnosis and treatment, and teach you all 9 major succulent pest and disease control methods!

No. 1 Scale insects

Tiny scale insects are often seen parasitizing on leaves. They are usually white, do not move much, and hide in the leaf center where they are hard to find. How should they be removed and prevented from multiplying in large numbers?

The small white insects in the picture above are scale insects.

Scale insects are protected by a hard shell, so once an infestation occurs, it is very difficult to kill them. Scale insects are most commonly seen on succulents in Cactaceae, Euphorbiaceae, Liliaceae, Aizoaceae, and jade-type succulents.

Scale insects reproduce quickly. Each adult lays nearly a hundred eggs at one time, twice a year. The eggs are powdery and, after drying and cracking, fly with the wind and spread to the stems and leaves of plants everywhere. In high temperatures, when they encounter moisture, they hatch into adults. At this time, the outer shell has not yet formed, which is the best time to eliminate them.

There are also many kinds of scale insects. They are covered with a waxy hard shell, round or oval. The former is about 3-3.5 mm in diameter, and the latter is about 2 mm long and 1 mm wide. When few in number, they parasitize near the areoles of plants or on the back of leaves and inside leaf sheaths. When numerous, they parasitize all over stems, branches, and leaves, sucking plant nutrients.

Treatment method: When the number is small, immediately remove them with a bamboo stick or toothbrush, isolate the flower pot of the infested plant to avoid contagion, and use a brush dipped in diluted Jiebijie solution or high-concentration alcohol to scrub and kill the larvae and eggs.

Notes: Recommended most suitable agents

1. Huhuashen

Dilute 500 times and spray stems and leaves once a week. It can be eradicated in 2-3 treatments. The toxicity is general, but when using it, do not spray against the wind. Do a good job of ventilation, and wear a mask and gloves. After finishing the work, be sure to bathe and change clothes.

2. Baijiu mixed with water at a ratio of 1:2.

When treating insects, water the surface layer of the potting soil thoroughly. Scale insects begin activity in spring when the room temperature is 7 °C. It can be watered once in mid-April, and thereafter about once every half month. Four consecutive treatments are effective.

3. Edible vinegar (rice vinegar)

50 ml. Soak a small cotton ball in the vinegar, then gently wipe the affected stems and leaves of the ornamental plant with the wet cotton ball. The scale insects can be wiped off and killed. This method is convenient and safe. It can not only achieve the purpose of insect removal, but also make the damaged leaves turn green and shiny again.

4. Alcohol

Gently wipe the diseased plant repeatedly, and the scale insects can be removed, and removed very cleanly and thoroughly. If alcohol is used to wipe diseased orchid leaves, not only can the scale insects be removed, but even larvae that cannot be seen clearly with the naked eye can all be thoroughly killed. In the second year, scale insect damage is rarely found. This method is simple, safe, and effective.

5、Diesel, laundry detergent, water

Mix into a mother liquor at a ratio of 10:0.6:6. At this time, the mother liquor contains 60% and is milk-like. After diluting with water to a medicinal liquid containing 30% oil, carefully spray it on scale insects on Aglaia odorata, kumquat, and sago cycad. After one week, most of the scale insects change from their original fresh orange color to a shriveled state, indicating that this method has a good control effect on scale insects.

No. 2 Anthracnose

Small black spots appear on the leaves. What disease causes this?

The black spots in the picture above are anthracnose.

Causes of the disease:

It usually occurs where planting is too dense, ventilation is poor, or there are wounds. The main damaged part is the stem. Water-soaked light brown small spots appear on stem nodes or near the edges, then expand into round to oval or semicircular to irregular brown spots.

Treatment method:

In the early stage of the disease, brown sunken spots appear. In severe cases, the center of the lesion has gangrene. It is difficult to cure. When purchasing, check whether the plant has this disease and avoid buying it. When the disease occurs, be sure to cut off and burn the diseased parts, then use special agents such as anthracnose Fumei.

No. 3 Rust disease

A flower lover asked: Rust-colored spots like rust appear on the leaves. What disease is this?

The picture above shows rust disease.

Causes of the disease:

It is mainly caused by improper cultivation management, such as potting soil that is too poor, insufficient nutrients, or long-term poor ventilation in pot cultivation, direct watering at the top of the plant, and unsuitable environmental factors triggering rust fungus infection.

This disease occurs on the plant epidermis. In the early stage, swollen small spots appear on the stem epidermis, with a yellow or reddish-brown center, then slowly expand outward. In severe cases, the marks sink and form ulcers, the tissue turns black, and even death occurs.

Treatment method:

In addition to paying attention to management, ventilation should be strengthened and watering at the top of the plant should be avoided. Spray 12.5% diniconazole wettable powder at 2000-3000 times dilution or amobam at 1500-2000 times dilution, spraying once a week.

No. 4 Root mealybugs

White cotton-like, thread-like symptoms appear on the plant roots. What disease is it exactly, and how should it be solved?

The picture above shows root mealybugs.

During the plant dormancy period, when the potting soil is dry, root mealybugs have strong reproductive capacity and will crawl out from the bottom of the pot and invade other pots. In severely affected plants, the soil near the roots becomes white, and water cannot penetrate.

Pest judgment:

This pest mostly parasitizes plant roots. Its body length is about several millimeters, covered with white powder, and the parasitic site forms a swollen mass.

Treatment method:

Mix Huhuashen with water and pour it into the growing medium, or use "Guoguang Jiebizhi". Of the two, Huhuashen is less harmful and has a preventive effect. If parasitism has already occurred, the plant can be taken out, washed clean, the root mealybug-parasitized parts cut off, and replanted in new soil.

Diazinon can also be used, which can remove most pests. They can only be used occasionally on non-edible plants and cannot be used on plants grown for food. Be sure to carefully read the method of use and dilution ratio.

No. 5 Spider mites

Spider mites appear on potted plants at home, and if not noticed, they spread to nearby plants. How should they be prevented and eradicated?

The picture above shows spider mites.

Spider mites reproduce quickly in dry periods, and spraying water on leaf surfaces has an inhibitory effect on damage. Among damaged ornamental flowers, Cactaceae, Aizoaceae, Euphorbiaceae, and Liliaceae are relatively common.

Spider mites are about 0.5 mm in diameter, crawl quickly, are small in size, and are not easy to find. They often gather in groups and gnaw on the epidermal tissue of stems and leaves, making the damaged areas appear mottled and rough, in an unsightly white or yellow color.

Treatment method:

Spider mites easily develop resistance. Using one drug for a long time will reduce its effectiveness. Currently used drugs include imidacloprid, nicotine, and carbofuran. Pyrethroid insecticides have very poor effects on them, and insecticides such as Radar on the market have little effect. The above drugs are relatively easy to buy, but carbofuran is highly toxic and should be used with caution.

Flower lovers can also use mosquito coils for sealed fumigation, 30-60 minutes each time.

PS: The method of making homemade chili water is simple. Just crush fresh chili and garlic, then mix with water. However, the effect is not as good as insecticidal agents, and it is suitable for preventive use beforehand.

No. 6 Aphids

A flower lover asked: Dense groups of aphids gather on plants. How should they be eliminated?

The picture above shows aphids.

Varieties prone to pest damage include succulents in Crassulaceae and Asteraceae, as well as Pereskia in Cactaceae, which are all relatively common.

Pest damage:

Aphids can reproduce 5-10 larvae in one day. Newly born ones are generally gray-green pests, about 1-2 mm long. They gather on plants near branches or on new buds, pierce plant tissues with needle-like mouthparts to suck nutrients, and young leaves often curl into tubes because of this. That way, flower lovers instead cannot see the aphids, which is really frustrating.

Treatment method:

Use a 500 ml cola bottle to mix a bottle of Huhuashen pesticide, pour it into a spray bottle, and then spray it evenly on the plants. Spraying must be comprehensive and careful. Clear surrounding weeds and ensure the environment is clean, which also has a preventive effect.

No. 6 Snails and slugs

The leaves have clearly been bitten in a ring shape. What pest causes this? How should it be solved?

Causes of pest damage:

When the climate is warm and humid, snails and slugs increase and reproduce quickly. These soft-bodied small insects can be found in both urban and rural areas. Once more plants are grown, they can be discovered.

Generally speaking, these soft-bodied small insects are usually snails and slugs. Many flower lovers say they cannot find them because they hide in moist, dark places during the day and only come out at night to forage. They not only gnaw young branches and tender leaves, but do not even spare old stems and leaves.

Treatment method:

Clear weeds, garbage, bricks, tiles, and other piled materials around the flower pot. Keeping things clean can effectively prevent them. In addition, install gauze netting around the flower pot for isolation, or buy special effective drugs for killing snails. Lime or salt can also be scattered beside the flower pot, but do not sprinkle it into the soil.

No. 7 Ants

A flower lover asked: Ants do not directly bite and eat plants. Will they harm plant health?

Of course they are very harmful. They are the biggest accomplices in damaging succulents.

The picture above shows ants.

Reason for damage:

Because ants like to eat the secretions of aphids, mealybugs, scale insects, etc., they often carry these pests from diseased succulents to other succulents. They are truly detestable. These ants not only protect the survival of pests, but also eat the honeydew secreted by the pests. They collude with each other and are the biggest accomplices harming plants.

Control methods:

When buying potted plants, carefully check the surroundings and the bottom of the pot to see whether ants appear, because once ants are present, it means other pests may exist. When ant damage occurs, ordinary insecticides can be used.

No. 8 Large caterpillars

A flower lover asked: A fat caterpillar is seen on a potted plant at home. What should be done?

The picture above shows a caterpillar.

Pest damage:

Some succulents near small shrubs and trees are prone to this kind of caterpillar. Some are blown by the wind onto ornamental plant plants, some crawl onto succulents from dark places at night, and the most detestable is a kind of black cutworm lurking in the soil, which specializes in eating young tender stems and leaves of plants and mainly feeds on succulents.

Treatment method:

Clear weeds around the flower pot and set up gauze netting. Generally, oily insecticidal liquids on the market are very effective against caterpillars, but when using them, be careful with the plants, otherwise the plants are prone to phytotoxicity. If one or two are found, just pick them off directly and kill them.

No. 9 Fungus gnats

Fungus gnats are something like mosquito larvae, but they do not live in water, and they can fly. They are present in warm, humid environments and reproduce very quickly. They are really annoying!

The image above shows fungus gnats

Pest and disease damage:

In fact, the main damage to plants is the scars left behind after they feed, and they also reproduce very quickly, which simply looks terrible.

Treatment methods:

They can mainly be killed with household pyrethroid insecticides. For the soil, you can use Huahuashen (Flower Guardian) as a soil drench plus spray the plant, or bury carbofuran in the soil. Be careful to use a small dose, as using only one type of pesticide easily makes the insects develop resistance; you can also fumigate with a small piece of mosquito coil, which is effective against the adults, but it cannot kill the larvae hidden in the soil!