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How to prevent and control cotton root rot in northern Xinjiang? Understanding the patterns of occurrence is key
In 2007, northern Xinjiang suffered varying degrees of cooling and rainfall in April, May and August respectively, and cotton root rot occurred rather severely, with the disease incidence in cotton fields reaching 20%-50%, causing a certain impact on cotton yield in northern Xinjiang. 1. Disease symptoms The pathogen overwinters as chlamydospores on plant residues in the soil and germinates to infect the following year. After cotton is infected, the leaves shrink or wilt, and soon afterward the plant lodges and dies. The stem base and roots of diseased seedlings are purplish brown and gradually rot, with the cortex drying and rotting; when pulled from the soil, the roots are decayed brown.
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How to prevent and control soybean anthracnose? Detailed explanation of occurrence patterns and control techniques
1 Disease symptoms A considerable portion of infected seeds die in the soil before emergence. The disease can occur from the seedling stage to the maturity stage. The pathogen can invade young stems from the cotyledons, damaging stems and pods, and also damaging leaves or petioles. 1.1 Cotyledon disease symptoms The disease can occur from the seedling stage to the maturity stage. On the emerged cotyledons there are dark brown lesions with slightly lighter edges. After the lesions expand, cracking or sunken areas often appear. When the climate is humid, the cotyledons become water-soaked and quickly wilt and fall off. 1.2 Leaf disease symptoms When leaves are infected, the lesions are irregular in shape, with dark
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How to prevent and control soybean phytophthora root rot? Detailed explanation of occurrence patterns and control methods
After soybean phytophthora root rot was introduced into our prefecture with the transfer of soybean seeds in July 2005, our station immediately established a soybean phytophthora root rot monitoring leading group and dispatched professional and technical personnel to carry out field monitoring work in Gongliu County. 1. Disease investigation In 2005, the affected area was 2239 hectares, and in 2006 the affected area was 2858 hectares. 1. Disease situation in Xinyuan County The soybean planting area was 0.67 million hectares, the investigated area was 0.3 million hectares, and the affected area was 0.23 million hectares, of which the sporadic occurrence area was 0.2
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Occurrence Patterns and Control Methods of the Soybean Hawkmoth
Damage symptoms: The soybean hawkmoth feeds on leaves as larvae. Young larvae eat leaves into a net-like, notched pattern, and after the third instar the larvae can eat all the soybean leaves, preventing the plants from setting pods and greatly affecting yield. Occurrence patterns: Mid-to-late July to early August is the peak period for adult egg-laying, late July to late August is the peak period of larval damage, and in early September the light-yellow mature larvae enter the soil to overwinter. Life habits: Adults: Adults hide by day and come out at night, and have a strong tendency toward black light lamps. They begin activity in the evening and are strong fliers with strong migratory ability. They mate at night, and lay eggs 3 days after mating. Eggs are mostly scattered on the undersides of soybean leaves, generally 1 to 2 eggs per leaf, and the eggs hatch into larvae after about 7 days. Larvae: Larvae are photophobic, mostly staying on the undersides of leaves or on stems during the day, and feeding strongly at night; on cloudy days they can feed all day. First and second instar larvae eat little and generally do not move between plants to cause damage; after the fourth instar they have the habit of moving to cause damage; fifth instar larvae show a sharp increase in food intake, accounting for about 90% or more of the total food consumption. The larval stage lasts 30 to 35 days.
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Detailed Explanation of the Occurrence Characteristics and Control Techniques of Spider Mites on Soybean
The soybean spider mite is the carmine spider mite (Tetranychus cinnabarinus), belonging to the class Arachnida, order Acariformes, family Tetranychidae. In 2007, affected by high temperatures and drought, soybean spider mites broke out over an area of 120 million mu in Heilongjiang Province, causing severe soybean yield reductions. According to surveys, in recent years the damage from soybean spider mites has risen to a primary position, generally reducing soybean yields by 20-30%, and in severely affected plots by 70-90%. I. Morphological characteristics. The adult body length is 0.3-0.5 mm, reddish-brown, with 4 pairs of legs. The female mite body length is 0.5 mm, egg-shaped or pear-shaped, slightly broad and raised at the front end, slightly pointed at the tail, with fine long setae on the dorsal surface, and one black elongated patch on each side of the dorsum; overwintering females are vermilion red and glossy. The male body length is 0.3 mm, purplish-red to light yellow, spindle-shaped or pear-shaped. The egg diameter is 0.13 mm, spherical, colorless and transparent when first laid, gradually turning yellow with red. The larva has 3 pairs of legs, a round body, yellow-white, becoming egg-shaped and light green after feeding, with dark green elongated patches appearing on both sides of the dorsum. The nymph has 4 pairs of legs, light green to pale orange-yellow, with setae appearing on the dorsum.
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Occurrence Patterns and Control Methods of Major Tea Plant Pests During the Summer Tea Season
Due to the low-temperature rain and snow weather last winter and this spring, the overwintering generation of tea pests this year had a low population base and a delayed occurrence period, and damage during the spring tea season was relatively light. However, summer weather is more suitable for the occurrence and damage of pests and diseases, so monitoring and control work must be carried out effectively. The occurrence level of the camellia spiny whitefly was lighter than last year, but pest numbers in some tea gardens still exceeded the control threshold. According to a survey by the Songyang County Plant Protection Station: the peak period of overwintering adult camellia spiny whiteflies was April 15, with an average of 17.4 insects per 100 leaves, later and fewer than last year (April 5).
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A Detailed Guide to the Occurrence Characteristics and Control Techniques of the Tea Black Spiny Whitefly
The black spiny whitefly mainly feeds on tea plant sap from the undersides of leaves as larvae and excretes honeydew, which attracts sooty mold fungi and induces sooty mold disease; in severe cases, the tea plants turn pitch black. Affected tea plants have reduced photosynthetic efficiency, lower sprouting density, delayed sprouting, thin and weak buds and leaves, and severe leaf drop, which not only affects tea yield and quality but also seriously affects the vigor of the tea plants. I. Occurrence Characteristics This pest has 4 generations per year, overwintering as mature larvae on the undersides of tea leaves, pupating in March of the following year; the peak periods of the 1st to 4th generation larvae are in late May, mid-July, late August, and late September to early October, respectively.
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Occurrence Patterns and Control Methods of Cotton Seedling Diseases
Cotton seedling diseases are characterized by a concentrated onset period, generally occurring 15-30 days after sowing. The primary infection source comes mainly from the soil, with a small portion from seeds. Around April 20 this year, many provinces experienced continuous rainy and low-temperature weather, so seedling diseases are bound to be severe, and timely control measures should be taken in all areas. I. Symptom Manifestations (1) Damping-off. When cotton seedlings are affected before emergence, it causes seed and sprout rot. When disease occurs after seedling emergence, lesions initially appear as yellowish-brown and later turn black and sunken at the base of the young stem near the soil surface. The lesions gradually expand,
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Occurrence Patterns and Control Methods of Cotton Red Leaf and Stem Blight
Disease symptoms and occurrence patterns: Cotton red leaf and stem blight is an explosive disease that frequently occurs in the middle and late stages of cotton growth. It can cause leaves to turn red from bottom to top until they drop off. The leaf veins remain green, the leaf mesophyll turns red, and the leaves become thicker, brittle, and wilted before finally dropping. When the stem is cut open, it does not change color, which distinguishes it from cotton Fusarium and Verticillium wilt. Generally, in old cotton-growing areas, the disease is more severe in cotton fields with continuous cropping year after year, sandy soil, too shallow a plow layer, or insufficient fertilizer lacking potassium fertilizer. Drought in the middle and late stages, along with severe potassium and zinc deficiency in the soil, can also easily accelerate the occurrence of this disease.
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Occurrence and Control Methods of Common Cotton Boll Diseases
Cotton boll disease is a composite disease caused by multiple pathogens, often manifesting as boll rot, which affects both cotton yield and cotton quality. Losses caused by boll rot reach more than 10% of total production. Common boll diseases in cotton fields in Henan Province include boll blight, anthracnose, red rot, pink rot, black boll, and others. They mostly occur in rainy years in mid to late August, and are especially severe during consecutive rainy days with high temperature and high humidity. I. Symptoms of Boll Diseases Boll blight: This disease mostly occurs on mature bolls in the lower part of the cotton plant, starting from the base, suture, or tip of the boll. It begins as a dark bluish-green water-soaked area, gradually spreading to the entire boll, turning bluish-brown, and finally becoming black, oily, irregular lesions with gradually lighter edges, and the boundary between diseased and healthy areas is not obvious.
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