How to prevent and control flower diseases and pests? Common methods for preventing and controlling diseases and pests in home gardening

When using chemicals to prevent and control diseases and pests, a slight mistake can cause phytotoxicity in the plants. The symptoms of phytotoxicity on the leaves include leaf spots, scorching, perforation, withering, yellowing, whitening, leaf curling, thickened leaves, deformity, and leaf drop; on the flowers, they include scorched petals, bud drop, and flower drop. In severe cases, it can lead to the death of the entire plant. Once phytotoxicity occurs, the following emergency measures should be taken, which can significantly reduce the damage and help the plant return to normal.

(1) Spraying water: For phytotoxicity caused by systemic pesticides, immediately spray water to wash the affected plants to reduce the pesticide content inside them. If phytotoxicity is caused by applying pesticide to the soil, the soil should be heavily flooded. After flooding, pay attention to drainage and do not let water accumulate. Do this 2-3 times to wash away the pesticide residues in the soil.

(2) Spraying chemicals: If phytotoxicity causes leaf whitening, granular 50% sodium humate can be used. First dissolve it in a small amount of water, then dilute it with 3000 times water for foliar spraying, or use the same method with 500 times water to irrigate the soil. After 3-5 days, the leaves may turn green again. If the phytotoxicity is caused by copper ions in Bordeaux mixture, spraying 0.5%-1% lime water can neutralize it. If the damage is from lime sulfur mixture, on the basis of spraying water on the leaves and watering, spray a 400-500 times diluted rice vinegar solution to reduce the damage. When phytotoxicity occurs due to improper use of dimethoate, spray a 200 times diluted borax solution 1-2 times.

(3) Increasing fertilizer: After phytotoxicity occurs, plant growth is inhibited and vigor declines. After taking the corresponding measures above, fertilizer should be supplemented promptly and appropriately. Regardless of the type of phytotoxicity, foliar spraying with 0.1%-0.3% potassium dihydrogen phosphate solution, or mixed spraying with 0.3%-0.4% urea solution plus 0.2% potassium dihydrogen phosphate solution, once every 5-7 days for 2-3 consecutive sprays, can significantly reduce the losses caused by phytotoxicity.

(4) Injecting water into the main trunk: When preventing and controlling boring pests such as longhorn beetles and jewel beetles, if phytotoxicity is caused by excessively high pesticide concentration, immediately inject a large amount of clean water into the main trunk in the same way as pesticide injection. If it is phytotoxicity from acidic pesticides, add some quicklime to the injected water; if not, add some rice vinegar to the injected water to accelerate the neutralization and decomposition of the pesticide.

(5) Strengthening cultivation management: For plants affected by phytotoxicity, attention should be paid to 3 aspects in cultivation management: first, proper pruning, cutting off dead branches and removing dead leaves to prevent the dead parts from spreading or being infected by pathogens and causing disease; second, loosening the soil to improve soil permeability, promote root development, and enhance the ability to absorb water and fertilizer; third, using quick-acting fertilizers such as urea for foliar topdressing (spraying leaf fertilizer) to promote the rapid recovery of plant vitality.

When household gardeners do not have pesticides, they can use local materials such as washing powder, soap, tobacco-lime water, tea seed cake, garlic, plantain, derris, datura, and pyrethrum as raw materials to prevent and control diseases and pests, which can also play a very good role.

(1) Washing powder: Dilute neutral washing powder with 400 times water and spray on plants, once every 5-6 days for 2-3 consecutive sprays. It is effective against aphids, whiteflies, and red spider mites. To kill scale insects, use a 20 times solution, spray once a week for 2 consecutive sprays.

(2) Soap: Add 1 part soap to 50-60 parts water, melt with hot boiling water, and spray. It can prevent and control aphids, scale insects, and others.

(3) Soak 1 part tobacco in 10 parts boiling water. After the water cools, rub repeatedly several times, then remove and filter. Separately, take 1 part quicklime and add 10 parts water to make lime milk. Before spraying, pour the lime milk into the tobacco water, add 1 times more water, and stir evenly before spraying. It can prevent and control pests such as aphids, thrips, wax insects, stink bugs, leafhoppers, leaf rollers, and leaf miners.

(4) Grind tea seed cake and soak it in boiling water for 1 day and night, then filter, dilute with 20-30 times water, and spray. It can prevent and control aphids, snails, and slugs. Dilute with 100 times water and spray to prevent and control rust disease. Dilute with 10-15 times water and pour onto the soil to prevent and control various underground pests such as white grubs, cutworms, wireworms, and mole crickets.

(5) Mash garlic, extract the juice, add 20-25 times water, stir evenly, filter, and spray immediately. It can prevent and control aphids, red spider mites, nymphs of scale insects, gray mold, root rot, and others.

(6) Take 500 grams of fresh plantain, mash it, add 500 grams of water, boil, filter, and pour onto the ground to prevent and control underground pests; spray with a 4 times solution to prevent and control scarab beetles, stink bugs, aphids, red spider mites, and others.

(7) Derris contains rotenone, which has a relatively strong stomach poison and contact-killing effect on pests. Grind derris into powder, take 500 grams of powder, add 150-350 kg of water, then add 250 grams of neutral washing powder, mix and stir evenly, filter, and spray. It can prevent and control many pests such as aphids, red spider mites, inchworms, and bagworms.

(8) Take 500 grams of fresh datura, chop it, add 5 kg of water, boil for half an hour, filter, and spray. It can prevent and control aphids, red spider mites, corn borers, and others.

(9) Pyrethrum has a strong contact-killing effect and a weak stomach poison effect on pests. Grind sun-dried white pyrethrum into powder, take 50 grams of powder, add 10-20 kg of water, stir, filter, add a small amount of neutral washing powder, mix well, and spray. It can prevent and control pests such as leaf rollers, leaf miners, stink bugs, aphids, thrips, and wax insects.