The latest course on the techniques and methods of pest control of asparagus

Ipomoea aquatica was formerly known as water spinach, also known as rattan cabbage, spinach, arenaria, urn cabbage, empty cauliflower, bamboo leaf cabbage, etc., like high temperature and humid environment, suitable for moist soil, like sufficient light, not strict requirements for soil conditions, like fertilizer and water, white trumpet-shaped flowers whose stem center is empty, so it is called "hollow cabbage". It is widely cultivated as vegetables in rural areas of southern China. Next, let's take a look at the pest control techniques of asparagus.

Brown spot of Chinese cabbage

[harm symptoms] the disease spot on the leaf is nearly round, sometimes limited by the large leaf vein, and becomes semicircular or irregular, and the diameter of the disease spot can reach 5-10 mm. The disease spot is brown, dark brown or reddish brown, which varies from variety to breed, usually with a dark edge and a light middle color. A small spot is embedded in the middle of most plaques, the center is light, the edge is dark, and several plaques can be fused into larger patches. After the disease spot develops along the main vein, the leaf can be twisted. Crack in the middle of the lesion when it is dry. When damp, the spot is black and moldy on both sides.

[induced pathogen] the pathogen goes out of season in the disease residue, and the disease residue produces conidia, which spreads with wind and rain and causes primary infection. After the disease of the plant, conidia were produced on the disease spot, which continued to spread and infect. Re-infection can occur many times in a growing season.

[agricultural control] ① reasonable fertilizer and water: reasonable fertilization according to the characteristics of varieties, increase the application of rotten organic fertilizer, pay attention to the combination of nitrogen, phosphorus and potassium, prevent vegetable plants from being de-fertilized, reasonable watering, do not over-irrigation, timely drainage after rain, reduce humidity. ② removed the old leaves: the seriously diseased fields were rotated for more than 2 years, and the diseased old leaves at the bottom of the vegetable plant were removed in time. ③ cleaning the garden in time: after harvest, remove the sick and residual body in time, turn the soil deeply, and root out the weeds in the field.

[chemical control] at the initial stage of the disease, you can choose to spray 1200-1500 times of 25% trimethoprim wettable powder, 1000-1300 times of 50% prohydantoin wettable powder, 1000 times of 70% mancozeb wettable powder, 65% mancozeb 500-600 times, 70% thiophanate wettable powder or 75% chlorothalonil wettable powder. Spray once at intervals of 7-10 days and use medicine 3-4 times.

White rust of Chinese cabbage

[harmful symptoms] White rust of hollow cabbage mainly harms the leaves. At the onset, the leaves appear yellowish green to yellow spots on the front, then turn brown, the disease spots are larger, and the back of the leaves are protuberant sore spots, close to round or oval or irregular shape. When the leaves were seriously damaged, the disease spots were dense, the diseased leaves were deformed, the leaves fell off, the stem swelled and deformed, and the diameter increased by 1 to 2 times.

[condition of onset] the temperature of 20-35 degrees is the most likely to develop the disease.

[chemical control] 35% metalaxyl seed mixture with 0.3% seed weight. At the initial stage of the disease, 58% metalaxyl manganese zinc wettable powder was sprayed 500 times, 40% triethyl aluminum phosphate (frost plague) 250 times 300 times, once every 10 days, for 2 times in a row.

[agricultural control] selection of disease-free seeds, 2-3 years of rotation, good disease control effect, pay attention to field sewage discharge and ventilation, reasonable arrangement of density.

Anthracnose of hollow cabbage

[harmful symptoms] Colletotrichum gloeosporioides mainly harms leaves and stems, and seedlings are easy to die. The leaf is infected, the disease spot is nearly round, dark brown, the spot is slightly wheeled, there are dense small black spots, the disease spot is enlarged and fused, the leaf turns yellow and dry, and the disease spot on the stem is nearly oval, slightly sunken inward.

[disease conditions] High temperature and rainy, excessive application of nitrogen fertilizer, overgrowth, overlapping stems and leaves without light, easy to occur.

[control methods] spraying 70% carbendazim wettable powder 800 × 1000 times or 50% thiram powder 600 times, 40% polysulfide suspension 500 times, 77% can kill 600 times, 10% difenoconazole water dispersible granules (Shigao) 50 × 75 g / mu, 80% Bordeaux liquid wettable liquid (essential) 300 × 500 times, 25% bromazonil wettable powder (carbendazim) 2000 × 2500 times, once every 10 days, continuously for 3 times. Stop taking medicine 5 days before harvest.

Ring spot of hollow cabbage

[harmful symptoms] the main harmful leaves were small brown spots on the leaves at first, round, oval or irregular shape after expansion, reddish brown or light brown, large disease spots with obvious concentric rims, and small black spots on the later round spots.

[disease conditions] when it is rainy and the growth is closed, the disease is easy to occur.

[chemical control] at the initial stage of the disease, spray 1 Vera 0.5 Val 160 200 Bordeaux solution or 45% Dysenamine aqueous solution 1000 times, or 75% Chlorothalonil wettable powder 600 times 700 times, or 58% Metalaxyl manganese zinc wettable powder 500x solution, 50% imidamide wettable powder (Polydo) 35g / mu, 70% propionium zinc wettable powder (Antaisheng) 150g / mu, 10% difenoconazole water dispersible granules (Shigao) 3550g / mu, 710g / mu For 2 or 3 times in a row.

[agricultural control] remove withered leaves and diseased bodies from the ground in winter, and combine with C to turn deeply to accelerate the decay of the remains. 1-2-year rotation can be carried out.

Spinach leaf curler

[damage characteristics] most of the newly hatched larvae ate the mesophyll and showed small white spots in the heart leaves and tender leaf sheaths of rice seedlings, as well as in the tips of rolled leaves damaged by old buds and rice thrips. The 2nd instar larvae gnawed on the mesophyll and left the skin, showing a short white strip, spinning longitudinally curled leaf tip 1.5-5 cm. The 3rd instar larvae gnawed on the mesophyll with white spots, and the bracts of the longitudinally rolled leaf insects were 10-15 cm long. The 4th instar larvae overate the leaves and eat meat and leave the skin. One larva can eat 6-10 rice leaves.

[agricultural control] ① uses bunches or heaps of grass to trap overwintering mature larvae. ② killed the overwintering larvae of fallen leaves, cracks or buildings in autumn and winter, killed the newly hatched larvae in summer, and removed the injured leaves if necessary. ③ placed black light to trap and kill adults.

[chemical control] attention should be paid to the prevention and control of the third generation and the fourth generation in Shandong and Jiangsu and Zhejiang provinces. 1000 times of oil or 1500 times of double-acting phosphorus EC, 1000 times of crystal trichlorfon, 1000 times of imidophos, 1500 times of Regent and 1000 times of phoxim were sprayed before rolling leaves at the end of the second instar.