Morphological and Biological characteristics and Flower and Fruit Protection techniques of Juglans regia in Hezhang County

Morphological and Biological characteristics and Flower and Fruit Protection techniques of Juglans regia in Hezhang County

1 Morphology and biological characteristics of a walnut in Hezhang County

The investigated walnut is located in Qianbuga Village, Cishen Town, Hezhang County, 70 years old, DBH 54 cm, height more than 12 m, more open posture, round crown shape, tree potential, weak branching ability, lateral bud fruit branch number 2, developmental branch length 10: 30 cm, leaflet shape long oval, no top leaf degradation phenomenon, leaflet number 711, 9, green, leaf tip shape acuminate, leaf edge shape entire. The heteroplasticity of male and female flowers is the same period of male and female, and the female tree begins to blossom and bear fruit more than 5 years after sowing. The length of inflorescence axis is 2.5 cm, the number of fruit per branch is 5: 10, more than 6, high yield, strong continuous fruiting ability, germination period is early April, leaf expansion period is mid-April, deciduous period is mid-October, early April of male flower, mid-April of female flower, early April of female flower, mid-April of female flower. The fruit ripening period is late September.

The thickness of green skin is 6 mm, the shape of nut is oblate, the surface of core and shell is lighter, the shape of fruit top is pointed, the shape of fruit shoulder is smooth, the shape of fruit bottom is flat, the suture line is flat, the density of suture is weak, the longitudinal diameter is 29.49 mm, the transverse diameter is 24.38 mm, the lateral diameter is 27.20 mm, the weight of single fruit is 6.01g, the kernel rate is 58%, the thickness of core shell is 0.94g, the inner fold wall degenerates, the diaphragm is membranous, the nucleolus is fuller, the color of nucleolar skin is light yellow, and the nut is uniform. Nucleolus fat content is 71.16%, protein content is 16.76%, nucleolus flavor is good.

Technology of flower and fruit protection of 2-string walnut

2.1 Control of diseases and insect pests

2.1.1 Black spot of walnut

Walnut black spot occurs on walnut leaves, twigs, flowers and fruits. After the leaves are damaged, near-round and polygonal brown spots appear on the veins of the leaves, which can heal each other when they are serious, and there are water-immersed halos around the lesions. A few diseased leaves appeared perforation in the later stage, the diseased leaves were wrinkled and deformed, and the disease spot on the petiole was long brown and slightly sunken. In severe cases, the disease spot extended to the tender branches and tender leaves. When the branches were surrounded by one circle, the branches above the disease spots withered. Inflorescence susceptible, first produce black water stains, can not expand, rachis blackened, bent, so that early fall. The disease first appeared black spots on the fruit, showing waterlogging, and then the disease spots expanded rapidly, resulting in the blackening of all the pericarp, the young fruit invaded the nucleolus, the blackening of the core shell caused early fruit drop, and the later damage to the fruit was limited to the exocarp.

2.1.2 Walnut anthracnose

After the disease of the fruit, brown spots appear on the green pericarp at first, and then turn black. The disease spot is nearly round and sunken, and there are small dark brown in the center of the disease spot, sometimes arranged in a wheel pattern. When the humidity is high, the small black spots on the disease spots become pink protuberances, that is, the conidia and conidia of the pathogen, and there are multiple disease spots on one fruit. After the disease spots are connected into pieces, the whole fruit becomes black and rotten and has no edible value, and some nucleoli rot and stink, resulting in early fruit drop. After the leaf is infected, the disease spot is irregular, and the disease spot spreads withered and yellow around the leaf edge. When the humidity is high, pink mucus appears on the small black spots of the disease spot. After the buds and twigs of seedlings and young trees are infected, they often wither down from the top, and the leaves are scorched yellow.

2.1.3 Walnut lifting limb moth

The larvae drill into the green peel and nucleolus of walnut, and the damaged pericarp gradually becomes black and sunken and falls early. In general, the damaged fruit rate of walnut is 10% ~ 20%, and when the damage is serious, the rate of insect fruit is up to 50% ~ 80%. There are 1-2 generations a year. At noon in the morning, adults often perch on the back of walnut leaves or grass rocks, lift their hind feet, keep shaking, sometimes jump, and walk with front and middle feet. Most of the flying, mating and spawning occurred at 17: 20, and the peak of activity was from 18 to 19:00. Most of the adults lay eggs in the gap, calyx fovea and peduncle at the junction of the two fruits, and the eggs were scattered, producing 1-2 eggs per fruit. the adults had a slight phototaxis, the life span was 3-8 days, and the egg period was 5-8 days.

2.1.4 Walnut elephant

One generation a year spends the winter with adults. At the beginning of April, walnut trees begin to sting and nibble on young buds and tender leaves to supplement nutrition. In mid-May, the number of stinging adults increases greatly. When the temperature reaches 16 ℃, the eggs hatch in the pericarp after 4 to 8 days. The newly hatched larvae eat the pericarp in the original pericarp for 3 to 4 days, then eat the nuts in the kernel, and constantly push the black brown worm dung out from the borer hole. The kernels gradually blackened and eroded, causing fruit drop. It usually takes about 20 days from spawning to fruit drop [Jishan Huayao].

2.1.5 Prevention and control measures

In the breeding of disease-resistant varieties, the planting density should not be too dense, and the crown should be ventilated and transparent. Strengthen comprehensive management, maintain strong growth of trees, improve disease resistance, clean up diseased branches, leaves and fruits in time to reduce pathogens, and strengthen pest control.

Intercropping with forest and grain, ploughing the tree disk, destroying the ecological environment of the larvae over the winter, reducing the water content of the topsoil, or burying the larvae into the deeper soil layer, the mortality of the overwintering larvae was greatly increased. During the fruit drop period of walnut weevil from early June to early July, stick to 1-3 days to pick up pests and fruits and bury them deeply, or before a large number of long-standing elephants go up to the tree to lay eggs, in the first and middle of May, the crowns were sprayed with 1000 times of phoxim, 3000 times of 2.5% deltamethrin, 3000 times of 20% cypermethrin and 48% of chlorpyrifos 300 times. Generally spray the soil on the tree plate three times to prevent the adults from getting on the tree [3].

2.2 other measures

The main results are as follows: (1) the comprehensive scientific management of timely and reasonable fertilization, irrigation, pruning and thinning of male flowers of walnut trees can improve the nutritional status of walnut trees, reduce the number of flowers and fruits, increase the fruit setting rate, and increase its yield and quality.

(2) during the full bloom of female flowers, artificial pollination should be carried out to improve the condition of flower and fruit drop caused by poor fertilization.

(3) thinning fruit according to the fruit number of each fruiting branch after nut ripening is beneficial to improve the quality of nuts.

(4) spraying female flowers with gibberellin at flowering and fruiting stage is beneficial to improve flower and fruit drop and increase yield.