Occurrence and control of main diseases and insect pests of Areca

1, taro Phytophthora Blight (taro)
1.1   is a fungal disease, the main source of primary infection of bacteria infected seedlings and left field become a disease center. The incidence of the disease and epidemic mainly depends on local rainfall and number of rainy days, the disease usually occurs in March to April, 6~8 month is the peak incidence, low-lying, poor drainage, planting density, planting field nitrogen fertilizer, the occurrence of severe disease.
1.2   symptoms: major damage to leaves, petioles and bulbs. The primary leaves round brown spots, after gradually expanding into round or irregular shape round grain spot, spot edge around the dark green hygrophanous band, high humidity spot surface layer of white powder, and mixed with yellow to brown necrotic tissue secretory droplets. Many lesions from the central hole only serious corruption into the veins are broken umbrella. The resulting petiole size ranging from dark brown irregular spots, surrounding tissues and around the lesion faded yellow, contiguous petiole expansion, petiole rot lodging, leaf wilting, corm Tissue Browning and decay of some victims.
1.3   control method:
(1) planting resistant varieties, the implementation of rice and rice rotation, the use of non disease taro species, seed disinfection before planting.
(2) clean the field, increase the application of P, K fertilizer to avoid partial application of N fertilizer.
(3) early drug prevention and treatment, June is the key to the prevention of the disease, drug can choose 25% metalaxyl wettable powder 600~700 times; 58% Laredo Mir WP 500 times liquid; 80% students wettable powder 600~800 times liquid, 75 kg per mu liquid, once every 7~10 days, 3~4 times continuous.
2, taro blotch
2.1   is a fungal disease, much against the weak growth of plants, high temperature and high humidity weather, field shadowing or partial nitrogen taro strains prosperous and not strong, are easy to induce the disease.
2.2   symptoms: the disease only damage the leaves, early pale yellow after gradient brown to dark brown, nearly circular lesion or shaping, diameter 1~0.3cm, edge boundary is not obvious, like stains, abaxial leaf color is shallow spots of leaf lesion, high humidity spot 'dark looming dark fuliginous mildew layer. Yellow leaves withered seriously.
2.3   control method
(1) pay attention to sanitation, promptly clean up the disease remains buried or burned.
(2) strengthening field management to enhance the resistance of taro plant.
(3) plots the onset of heavy start spraying 50% thiophanate methyl WP 600 times liquid in the early stage of the disease; 75% chlorothalonil WP 600 times liquid, 80% or Johnson 600 times liquid spraying to spray back of leaf and leaf, every 7~10 days a time later 2~3.
3, taro soft rot
3.1   is a bacterial disease, spring from the plants in the field was removed by invasive wound. When the petiole base or underground bulb wound in a long time in high temperature conditions prone to disease.
3.2   symptom: major damage to petiole base or bulb. Petiole of primary disease, water soaked, dark green, no obvious edge lesion expansion after the internal organization of brown rot or petiole leaf yellowing and folded down, the disease gradually infected corm rot disease of hair play rapid softening, corruption, and finally all withered and scattered the stench of lodging, disease taste.
3.3   control method
(1) selecting resistant varieties.
(2) 2~3 year rotation.
(3) to strengthen field management, especially organic manure compost; incidence of plants began to rot or water fermentation to timely drainage of the rice field, and then sprayed copperoxychloride 30% SC 600 times liquid; 72% streptomycin soluble powder 3000 times liquid; kocide 2000 1000 times liquid above an optional application of liquid medicine, mu 75~100 kg, once every 10 days, consecutive 2~3.
4, Spodoptera litura
4.1   the omnivorous insects belong to the insect, year 7~8 generation, there are 3 main damage period, damage of taro is mainly 7~9 in the third and four generation, mainly in the larva taro plant leaves, 1~2 larvae feeding back Cluster leaf mesophyll, leaves become yellow white, translucent mesh film, 3~4 larvae dispersed feeding, leaf bitten notch and even eat, insect population will cause devastating disasters. General 7~9 month rainy high temperature, the insect serious.
4.2   control method
(1) removing the eggs and larvae of artificial destroy, field investigation, picking luankuai destroy; when it was found that the new network will be back damaged leaves, leaf cluster larvae, artificial killing.
(2) when the field to check 5 head / m2 larvae, as the control target field, timely medication control, pesticide should be carried out in the evening before, agents can choose 5% Regent 2000 times liquid, 80% dichlorvos EC 800 times liquid; 4.5% high return Xiaoshun permethrin EC 2000 times, once every 10 days 2~3, consecutive.
5, the underground pests: mainly cutworm, grubs, mole crickets, pest mainly affects the main quality of taro corms of taro corms, induced disease, the insect damage period in 4~9 months, with 3% control methods: isazophos granule is 4 kg / mu for soil treatment method, in taro seedlings before planting 3% isazophos fine granules mixed 50 kg dry soil in the planting hole in the shallow overburden after planting.
6, taro aphid: alias cotton aphid, Aphis gossypii Glover, with adults and nymphs suck sap in taro leaves and tender stems, the taro plant growth point of injured leaf curling, the insect to damage taro seedling. Prevention methods: pest inspection, when the detected rate of 15~20% strains, immediately medication control, a big hero, 2000 times liquid, 2.5% imidacloprid EC 2000 times liquid pesticide can choose 10%.