Pest and disease control techniques for flowers
1. Common Diseases
1.1 Peanut Bacterial Wilt
1.1.1 Symptoms. Peanuts are most susceptible to this disease during the initial flowering stage. In the early stages, the first and second leaves of the main stem wilt first due to water loss, delaying leaf opening in the morning. After 1-2 days , the entire plant or one side of the plant's leaves wilt rapidly from top to bottom, turning a dull, bluish-green color. Later, the diseased leaves turn brown and scorched.
1.1.2 Control methods. Apply Hejia'an (a traditional Chinese medicine) after rain on a sunny day or at the initial stage of disease before flowering.20 m1. Add water15 kgSpraying should be done every 7-10 days . 1.2 Stem Rot 1.2.1 Symptoms. In the seedling stage , the cotyledons turn blackish-brown and dry-rot, which then spreads along the petiole to the base of the stem, appearing as yellowish-brown water-soaked lesions, eventually turning into blackish-brown rot. In later stages, water-soaked lesions first appear at the base of the stem or on the main and lateral branches, initially yellowish-brown, then turning blackish-brown, causing the above-ground parts to wilt and die. 1.2.2 Control Methods. Implement reasonable crop rotation, thoroughly dry seeds before storage, sun-dry and select seeds before sowing, avoid using moldy or poor-quality seeds, and disinfect seeds by treating them with 50% carbendazim at 0.3% of the seed weight . 1.3 Root Rot 1.3.1 Symptoms. The base of the stem appears water-soaked and yellowish-brown, the plant is shorter, the leaves dry up from the bottom, the main and lateral roots turn brown and rot, and in the later stages only the brown, shrunken main root remains. 1.3.2 Control Methods. Reasonable crop rotation, strict seed selection and sun-drying, seed treatment with 0.3% of the seed weight of 50 % carbendazim, and spraying the entire field with a 1000- fold dilution of 50% carbendazim at the initial stage of disease. 1.4 Leaf Spot Disease 1.4.1 Symptoms. Brown spot lesions are round, dark brown, and relatively large, with a yellow halo around the outer edge, and gray mold appears in the later stages; black spot lesions are round, dark brown, without a yellow halo around the lesions, and are smaller than brown spot lesions. 1.4.2 Control Methods. Reasonable crop rotation, selection of disease-resistant varieties, and the hot and rainy months of July and August are the key periods for controlling leaf spot disease. At the initial stage of disease, spray with an 800- fold dilution of 50% carbendazim .
Apply a 600- fold dilution of liquid or 75% chlorothalonil wettable powder , or an 800- fold dilution of 70% mancozeb , once every 15 days , for a total of 2-3 applications . 1.5 Peanut Nutrient Deficiency and Control
1.5.1 Nitrogen deficiency. Peanuts deficient in nitrogen exhibit poor plant growth, smaller, pale yellow leaves, and impaired peg formation and pod development. The stems gradually turn red, root nodules form less, and branching is reduced. Control measures: Apply sufficient organic fertilizer; inoculate with rhizobia; increase phosphate fertilizer application to enhance nitrogen fixation capacity; apply 5-60 mg /acre of ammonium sulfate before flowering.10 kgIdeally, the fertilizer should be composted with organic fertilizer for 15-20 days before application.
1.5.2 Phosphorus deficiency. When peanuts are deficient in phosphorus, the leaves are dark green, the stems are thin and purplish, there are few root nodules, few flowers, and poor pod development. Control measures: Apply 15-20g superphosphate per acre.25 kgMix with organic fertilizer and compost for 15-20 days before applying as base fertilizer.
1.5.3 Potassium Deficiency. When peanuts are deficient in potassium, the initial symptoms are darkening of the leaves, followed by yellow spots at the leaf tips, which then develop into light brown-black spots. Eventually, the chloroplasts wither and scorch, while the veins remain green. The leaves become dehydrated and curl, and there are few or deformed pods. Control measures: Apply wood ash per acre.150 kgPotassium chloride or potassium sulfate 5 ~10 kgAlternatively, a 0.3% solution of potassium dihydrogen phosphate can be sprayed on the leaves.
1.5.4 Iron deficiency. Iron deficiency causes leaf tissue to lose its green color, and in severe cases, the veins also turn green. Control measures: Apply easily soluble ferrous sulfate as a base fertilizer, preferably mixed with organic fertilizer; soak seeds in a 0.1% ferrous sulfate solution for 12 hours ; spray the leaves with a 0.2% ferrous sulfate solution during the pegging or pod-setting stage , once every 5-6 days , for 2-3 consecutive times. 1.5.5 Calcium deficiency. Calcium deficiency manifests as poor development of pods and kernels, resulting in empty pods. Calcium deficiency often leads to " black embryos , " poor development of peanut shells, and easy rotting of pods. In severe cases of calcium deficiency during the seedling stage, leaves lose their green color, petioles break off, or the growing point wilts and dies, and roots do not differentiate. Control measures: Apply 15-200 mg/mu of superphosphate during the mid-growth stage.
20 kg2. Common Pests 2.1 Aphids. Aphids not only suck peanut sap but are also major vectors for virus transmission. To control peanut aphids, spray with
a 1000- fold dilution of 40% dimethoate emulsifiable concentrate ; pyrethroid pesticides can also be used. 2.2 Spider Mites. Spider mites in peanut fields mainly feed on sap by gathering on the underside of peanut leaves as adults and nymphs. Initially, small yellowish-white spots appear on the upper surface of the leaves; in severe cases, the leaves wither and die.
Shedding. Control methods: Apply 15% acaricide emulsifiable concentrate at a dilution of 1500-2000 times per acre , or apply acaricide per acre.30 gDilute with water30 kgSpraying control.
2.3 Cotton bollworm , bridge-building insect, and beet armyworm.
2.3.1 Damage symptoms. The larvae bite and feed on peanut leaves from the leaf edges, creating notches. In severely affected peanut fields, the leaves are completely eaten, resulting in bare stalks. This severely impacts peanut photosynthesis, pollination, and peg penetration, leading to a significant reduction in peanut yield.
2.3.2 Control methods. ① Agricultural control. Deep plowing and winter irrigation reduce the insect source and eliminate overwintering pupae. ② Chemical control. When there are more than 30 larvae ( eggs ) per 100 plants , and 30% of the eggs turn yellowish-white with some showing a purple halo, and some have already hatched, the optimal time for control is before the larvae reach the 3rd instar. Pesticides should be applied promptly. Foliar spraying with Bacillus thuringiensis or spraying with 1.8% abamectin EC at a dilution of 2000-3000 times; 10% imidacloprid WP at a dilution of 4000 times; 70% endosulfan EC at a dilution of 1000-1500 times; or 50% phoxim EC at a dilution of 1000-1500 times. ③ Biological control. During the initial peak of bollworm egg-laying, release 15,000 Trichogramma wasps 2-3 times each time . ④ Trapping and killing adult moths.
60 cmBundle 7-8 poplar branches of varying lengths into a bundle and evenly plant 150 bundles per hectare at dusk . Catch the insects in the early morning and kill them. Replace the bundles every 5-6 days . Alternatively, use black light traps. 2.4 Cutworms and Grubs 2.4.1 Symptoms. Cutworms and grubs are underground pests that cause significant damage over a long period. They often result in missing seedlings and gaps in rows in peanut fields, making them the most significant pest affecting peanut yield. Because these underground pests are highly concealed and difficult to control, integrated pest management is essential. 2.4.2 Control Methods. ① Reasonable Crop Rotation. Rotate with non-leguminous crops for at least two years to effectively disrupt the habitat of cutworms and grubs and reduce damage. Good preceding crops for peanuts include corn, millet, and other gramineous crops. ② Deep Plowing and Sun-drying of the Soil in Autumn. Deep tilling in autumn can bring pests to the surface, where they will die from sun exposure or be eaten by birds, reducing overwintering pest populations. ③ Apply well-rotted organic fertilizer. Add fertilizer according to the following ratio per cubic meter of manure.
25 kgThe ratio of ammonium bicarbonate, after thoroughly mixing manure and chemical fertilizer and sealing for composting, and then applying the treated and composted manure to the field before sowing, can effectively reduce the migration and damage of grubs. ④ Seed dressing. Before sowing, coat the seeds with a seed dressing agent, or use 50% phoxim emulsifiable concentrate.
500 mAdd 10 ml of water.50 kgSeed dressing 400 ~500 kgThis method can also effectively control rodent pests. ⑤ Soil treatment. Before planting peanuts, apply 5% phorate granules per acre along the peanut rows .
6 kgApplying the pesticide before rain or watering after application yields better results. ⑥ Root drenching method: Use 30% chlorpyrifos EC per acre .
600 m1 or 48% chlorpyrifos emulsifiable concentrate 350 ~400 m1% or 22 % imidacloprid EC450 m1. Apply the pesticide by drenching the roots along the ridges before rain or by watering after drenching. Alternatively, apply the pesticide with irrigation water, but the dosage should be 1-2 times higher than for drenching. ⑦ Control larvae. From late June to late July, during the peak hatching and larval stages of the scarab beetle, apply 35-45 ml of 5% phoxim granules per hectare.
45 kgAdd 250g of fine soil.300 kgScatter the pesticide around the peanut roots and hoe it shallowly into the soil; alternatively, drench the roots with a 1000- fold dilution of 50% phoxim EC or 90% trichlorfon crystals . ⑧ Trapping and killing adults. Black light traps can be used to kill adults when they are abundant. In areas where black velvet beetles are prevalent, 30~
40 cmLong, fresh elm and poplar branches can be soaked in a 30-40 times dilution of 40% dimethoate , and then inserted into peanut fields in the evening, using 10-20 branches per acre to attract and kill adult grubs. Alternatively, grubs can be manually killed while plowing the field during the autumn harvest, or ducks, chickens, geese, etc. can be released to prey on them.
Chemical control. The optimal time for chemical control is during the peak hatching period of white grubs (late July) and early August when young larvae are in their early stages. Apply 250-400 ml of 48% chlorpyrifos EC mixed with 20-25 kg of fine sand per acre , applying it to the area around the peanut plants . Alternatively , use an 800- fold dilution of 40% chlorpyrifos EC; remove the nozzle and spray the area around the plant roots. Application can be done before rain, or by diluting the solution with 40 kg of water and spraying the roots. Water immediately after application. This method effectively controls white grub damage.