Symptoms and prevention methods of the main pests and diseases of pomegranate

Symptoms and prevention methods of the main pests and diseases of pomegranate

Lin Yongqin

First, pomegranate disease and prevention

(1) Pomegranate melanoma

1. Symptoms of morbidity. Only harmful leaves are seen. At the beginning of the disease, the lesions are small black spots in the shape of a needle eye on the leaf surface, and then expand, showing round to multi-horny irregular spots; in the later stages, the spots are dark brown to black brown, and the edges are green and black lines. When the climate is dry, the central area of the disease department is gray-brown, and in general, the leaf surface is scattered with one to several disease spots, and in severe cases, it can reach 20, resulting in premature leaf loss.

2. Prevention and control methods. First, combined with winter pruning and fertilization, thoroughly clean up the stumps and leaves of the ground disease, enter the pit for fertilizer, and reduce the source of germs. Second, from late May to mid-September, with a lot of precipitation and rapid disease spread, 50% carbendazim sulfur gum suspension 500 times liquid, 80% complex pure wettable powder 600 times liquid, or 80% 600 times of indigo dasheng 600 times liquid should be sprayed on sunny weather every 15 days.

(2) Pomegranate cracked fruit

1. Symptoms of morbidity. Pomegranate cracking mainly occurs on near-ripe fruits, and the lateral longitudinal cracks of the fruit occur more often on fruits such as sunburn, dry rot, and coal pollution, and the severity is related to the season, weather changes and varieties. The fruit is easy to crack if the moisture supply is uneven or the weather changes greatly, and the fruit is suddenly sunny after heavy rain or continuous rain, and the cracked fruit is prone to occur when the temperature is high.

2. Prevention and control methods. The early production technology and high replacement head technology of pomegranate dense planting are adopted. It is recommended to plant about 110 plants per 667 m2 in a single dry type. Improve ventilation and light transmission conditions, and cover the garden with grass. In order to avoid uneven water supply during the growth period of the fruit, it is not possible to over-water in the later stage. Spraying 500 to 1000 mg/kg of specific solution per 667 m2 can reduce the occurrence of fruit splitting.

(3) Pomegranate burning

1. Symptoms of morbidity. Occurs from the shoulder to the yang part of the fruit waist. At the beginning of the disease, it loses its luster, looms oily, brown spots, and then becomes brown, russet to black large patches, and the diseased tissue is not obvious; in the later stage, the diseased part is slightly concave, dehydrated and hard, and the middle part often appears in the middle of the rice grain gray bubble, the diseased fruit forms a "scar face", the taste is poor, the necrotic peel is observed, the inner peel becomes brown, and the outer layer of the fruiting body burns.

2. Prevention and control methods. The orchard is irrigated in time, other diseases are prevented in time, and the fruit branches and leaves are protected and the normal growth and development are protected, which is conducive to preventing "sunburn". At the young fruit stage, try to remove the small fruits exposed to the sun at the top of the canopy and the outer layer of the western sun, so as not to become sunburned fruits after they grow up. In orchards prone to sunburn, the trunk can be whitened, and when pruning, more branches are left in the southwest direction to reduce the harm of sunburn.

(4) Pomegranate root

1. Symptoms of morbidity. The disease is mainly harmful to the roots and root neck. When the root occurs, no new roots or adventitious roots occur at the root, the root skin rots after rust, causing the upper part of the ground to wither, the leaf edge is scorched, and in severe cases, the leaves turn yellow, affecting flowering and fruiting, and the root time is long, often inducing root rot.

2. Prevention and control methods. Improve the soil environment, apply more organic fertilizers, increase phosphorus fertilizers and potassium fertilizers. Do a good job of trenching and drainage, and remove stagnant water in time after rain. Rationally shape and prune to adjust the load of fruit trees. Strengthen the prevention and control of other diseases and insect pests, promote root growth and development, and enhance the disease resistance of trees.

Second, pomegranate insect pest and control

(1) Pomegranate cotton aphid

1. Occurrence pattern. Pomegranate cotton aphid clusters on pomegranate buds, young stems, young leaves and flowers can cause buds to wilt and fall off, and the development of young stems is hindered. Eggs are used to winter in the branches of pomegranates and the stems of weeds such as summer dry grass and thorny vegetables, and when the average temperature of 5 d reaches 6 °C in February and March of the following year, the overwintering eggs become "dry mother" solitary females and give birth to several generations of female aphids, called "dry females", and produce winged aphids after breeding 2 to 3 generations. Winged aphids migrate from wintering hosts to melon vegetables and other housewarming hosts in April and May, until the air turns cold in early autumn and early winter, and the winged aphids migrate back to the wintering host, and the males and females mate and lay eggs for the winter.

2. Prevention and control methods. Initially sprayed with 10% imidacloprid wettable powder 1000 times liquid, or 2.5% kung fu emulsion 1500 times liquid.

(2) Pomegranate velvet

1. Occurrence pattern. The affected branches are thin and yellow, the tree is weak, and the tree that causes serious coal pollution disease will die when the whole tree is damaged. It can occur in 3 to 4 generations in 1 year, and the cracks in the dendritic layer, bud scales, and overwintering in the old skin occur in 2 to 3 years in the last nymph. In early to mid-April of the following year, the stings emerge, sucking the sap of young shoots and young leaves, and then transferring to the surface of the branches. Adults mate in early May, and each generation of nymphs hatches from late May to early June, with nymphs beginning to overwinter in mid-to-late July, late August to early September, and early October. The worm spreads over long distances mainly through seedlings, cuttings.

2. Prevention and control methods. Before budding in early April, spray the whole tree evenly with 3 to 5° Bé stone sulfur compound, or spray 21% bug bug killing emulsion 1000 times liquid. Each generation of nymphs is controlled with 20% pyrazine wettable powder 1500 times liquid or 2.5% kung fu emulsion 2000 times liquid sprayed.

(3) Peach borer borer

1. Occurrence pattern. 2 to 3 generations occur in 1 year.

The first larvae nibble on the peel tissue in the calyx or on the surface of the fruit, and after 2 years of age, they feed into the fruit to eat the young seeds, and a large amount of insect feces accumulates on the periphery of the borer hole, and the old mature larvae are in the trunk of the tree, inside the dead fruit, the branches fork, the crack tree hole, the decaying wood, under the bark, as well as the basket cracks, debris, rock cracks, etc. Overwinter, and the place is scattered. The overwintering adult moth period is in late April, the peak period is from late May to early June, lying still in the leaf back and weeds in the dense place between the leaves during the day, and after the night, it flies out of the active tail to lay eggs, and the eggs can be seen in 2 to 3 days of egg laying, and the generations overlap highly. Eggs are mostly scattered in the calyx, and there are also a small number of eggs laid on the surface of the fruit or the fruit stalk where the several fruits are adjacent, and the branches and leaves are shaded.

2. Prevention and control methods. In mid-June, the fruit is young

For example, when walnuts are large, block the calyx with 1: 100 times 90% of the dimethodium, or 50% octylthion mixed with loess balls. In combination with the blocking calyx, foliar sprays of 20% of the mixture of 2000 times of the solution are sprayed with 20% of the permethrin, or 2 to 2 times of the 2500 times of the solution, and the last one is carried out in early June during the peak of the overwintering adult egg laying.