How to control common pests and diseases of kiwifruit? Here are detailed measures for reference
Chen Zhong et al
Kiwifruit belongs to the genus Kiwifruit of the Kiwifruit family, and at all stages of growth and development, it will inevitably suffer from various pests and diseases. A variety of pests and diseases in the orchard often occur and affect each other, which virtually increases the difficulty of control for fruit farmers, and it is difficult for fruit farmers to seize the favorable opportunity to implement control. Therefore, it is suggested that in the specific prevention and control, we must study and formulate a more reasonable and feasible prevention and control plan according to the characteristics of different pests and diseases, adhere to the principle of "prevention first, comprehensive treatment, joint prevention and treatment", take a variety of measures to carry out scientific prevention and precise control, minimize the occurrence and frequency of pests and diseases, minimize the adverse impact on kiwifruit, strive to improve the quality of fruits, and help fruit farmers increase their income and get rich.
1 Common pests and diseases of kiwifruit
The common diseases of kiwifruit in Shandong mainly include brown spot, canker, gray mold, root rot, flower rot, cooked rot, etc., and the common insect pests mainly include mulberry white scale, beetle, Spodoptera exigua, red spider, aphid, leafhopper, etc.
1.1 Kiwi brown spot disease
Kiwifruit brown spot, also known as leaf blight, is most likely to occur in the rainy and humid season. The disease mainly affects the leaves (see Fig. 1), after the leaf is damaged, the initial leaf edge appears round lesions, dark green in color, with the passage of time, the lesions expand rapidly, brown and light brown alternately. In the later stage of the disease, the affected leaves curl inward, the leaves crack and die, and a large number of leaves and fruits fall in the trees, which threatens the normal growth and development of the tree, causes the tree to weaken, and seriously affects the effective improvement of the yield and quality of kiwifruit.
Fig.1 Kiwifruit brown spot disease
1.2 Kiwi canker disease
The disease mainly harms the leaves, new shoots and branches of kiwifruit, but does not harm the root tissue and fruits, and the disease is most serious on the branches of 1~2 years old. The leaves are infected, showing dark brown greened lesions, the outer edge of the lesions turn yellow within 5mm, the diseased leaves are curled and scorched, and they are easy to fall off early. The new shoots and branches are infected, at first there is a small spot like a water stain, and then the spot increases and becomes a diseased spot, and the cortex is longitudinally cracked, and the cracks flow out of the blue-white water-stained liquid, which slowly turns into a reddish-brown rust-like ulcer spot, which can lead to the shrunken and dead branches and leaves in severe cases.
1.3 Kiwi mulberry scale
The mulberry scale is a stinging pest with a life cycle divided into 3 stages: egg, nymph, and adult. The damage mode is to suck the sap of branches and leaves by nymphs and adults, and when it occurs severely, the shells on the branches are densely overlapped, and it looks like cotton wool covering the branches from a distance (see Figure 2). The damaged branches and vines are often underdeveloped, affecting the normal growth and development of the tree body and the formation of flower buds, causing the tree to weaken, the branches to die, a large number of fallen leaves, etc., the insect sometimes also infringes the fruit, after the fruit is damaged, it affects the value of the commodity, and a large number of bad fruits, rotten fruits, and deformed fruits appear when they occur seriously, and the trees die and the whole garden is destroyed.
Figure 2: Kiwi white scale
1.4 Kim Yongzi
Scarab is an omnivorous Coleopteran pest, there are many species, at present, there are big blackgill beetle, dark gill beetle, patina green beetle, Chinese arc beetle and so on. Scarab larvae, also known as grubs, mainly damage the young roots of kiwifruit, affect the nutrient transport of roots to above-ground plants, cause premature senescence of the tree, and early yellowing of leaves. Adults mainly eat the leaves and tender shoots of kiwifruit, and the damaged leaves are eaten with holes, and some have irregular notches, and the mesophyll is eaten when the harm is serious, leaving only the petiole and the main vein, which has a serious impact on the normal growth of kiwifruit.
1.5 Spodoptera exigua
Spodoptera exigua is a lepidopteran pest that mainly damages leaves, shoots and fruits. The larvae are harmful to the leaves, the light ones bite the leaves and are notched, and the heavy ones eat the mesophyll, leaving the leaf epidermis, leaving only the leaf veins, and the whole leaf is reticulated. Adults mainly damage the ripe and near-ripe fruits, with siphon mouthparts to break the peel, suck the pulp juice, the puncture holes are often concave, the depression often flows out of the gelatinous liquid, the damaged parts present water-stained oval patches, and then the fruit rots, and the fruit falls everywhere. In the extensive management of kiwifruit orchards, the occurrence of this disease is more serious.
1.6 Other pests and diseases
In addition to the above 5 common pests and diseases, there are also gray mold, root rot, flower rot, cooked rot, red spiders, aphids, leafhoppers, etc. During the growth period of kiwifruit, a variety of pests and diseases occur alternately and overlap, harming the leaves, trunks and fruits of the tree. Therefore, we should pay close attention to the dynamics of pests and diseases, and take a number of measures to effectively prevent and control them.
2 Countermeasures
2.1 Agricultural control
In the kiwifruit growing season, combined with orchard pruning, all the seriously damaged branches, leaves, flower buds, and fruits are cut off, and it should be noted that after the pruning of each kiwifruit is completed, the pruning tools are disinfected with 75% alcohol to prevent cross-infection of different pests and diseases through the pruning tools. Dead branches, long branches, and overly dense branches are also pruned and collected together with fallen leaves and fruits on the orchard ground, and burned in a concentrated manner, and the ashes are used as fertilizer and sprinkled in the fields. In winter, combined with winter pruning, cut off weakened branches, diseased and insect branches, scrape off old coarse bark, diseased spots, together with the dead branches and leaves on the ground, and transfer them to the outside of the garden for harmless treatment, so as to eliminate the hidden red spiders, scale insects and other pests and gray mold, brown spot and other pathogenic bacteria hidden in the winter.
2.2 Reasonable fertilization
During different growth and development periods such as the germination stage, new shoot growth stage, flowering stage, and fruit stage of kiwifruit, strip ditches and annular ditches were excavated in the park, and organic fertilizer was applied in a timely manner, and nitrogen fertilizer was applied less to meet the water supply and improve plant resistance. When fertilizing during the fruit expansion period, an appropriate amount of potassium fertilizer can be added, and foliar fertilizer should be sprayed many times, which can increase the thickness of the leaves and peel and improve the calcium content of the tree. After applying basal fertilizer in autumn and once after winter, water is irrigated to ensure that the nutrient storage of the tree is sufficient. Strengthen the management of flowering and fruiting period, timely thinning flowers and fruits, maintain a certain reasonable fruit loading, and avoid excessive loading, aggravating the weakening of the tree, and causing a variety of pests and diseases.
2.3 Physical Booby-Traps
Physical booby-trapping is a measure to trap and eliminate pests according to their tropism, according to phototaxis, hang a certain number of frequency vibration insecticidal lamps in the park, and carry out light trapping and killing of adult pests such as beetles and winged moths. According to the yellowness, hang a certain number of yellow plates to kill small insects such as aphids, mosquitoes and leafhoppers. According to the flavor attractance, hang the trap and fill it with sweet and sour liquid (1 part of sugar + 2 parts of vinegar + 20 parts of water + appropriate amount of liquor) to trap and eliminate moths, beetles and other pests.
2.4 Barrier Protection
Measures such as fruit bagging at the young fruit stage (see Fig. 3), whitening the trunk (see Fig. 4) and applying sticky shellac rings are adopted to block the invasion of pests and diseases and protect the tree from damage. 20~40 days after flowering, choose a single-layer wood pulp paper bag to bag the young fruits, which can effectively block the invasion of pests and diseases and pesticide pollution after bagging. In early spring, apply a shellac ring to the base of the kiwi trunk to prevent larvae from climbing the tree and preventing wingless female adults from laying eggs on the tree. In autumn, winter and early spring, prepare a whitening agent (10 parts of quicklime + 1 part of stone sulfur mixture + 40 parts of water), and evenly coat the trunk with a brush, which can play the role of sterilization and insect control.
Figure 3 Fruit bagging
Figure 4: The trunk is painted white
2.5 Biological control
Biological control has the advantages of not polluting the environment and having a long effective period, mainly including measures such as treating diseases and insects with beneficial insects, preventing diseases and insects with beneficial bacteria, and biological sterilization. For example, to control aphids, beneficial insects such as seven-star ladybugs, aphid flies, and parasitic wasps can be used to control mites, scales and other pests, and beneficial insects such as red-eyed bees, spiders, ladybugs, and bugs can be used. Bacillus thuringiensis can be used to control inchworms, poisonous moths, lamp moths, etc., and spring leimycin and mesomycin can be used to prevent and control canker disease, etc., all of which have obvious control effects. The law of biological sterilization is to use sexual attractants to lure male insects to come, prepare sterilization agents to make them contact, and then male insects mate with female insects, so that the offspring of fertilized female insects can not grow normally, so as to effectively reduce the number of pest offspring and achieve the purpose of preventing them from harming the tree.
2.6 Chemical control
To prevent and treat canker disease, you can use 5 Baumé stone sulfur mixture and 47% Spring Thunder King Copper WP 500 times liquid whole garden spray before kiwifruit germination. From March to April, 500 times of 0.3% tetramycin aqueous solution, 800 times of 3% Zhongshengmycin wettable powder, and 200 times of ulcer rot were used for the whole garden spray during the wound flow period of kiwifruit trees, which had a good effect on the prevention and control of canker disease. From bud to flowering, 5 Baumé sulfur mixtures are used to prevent and treat flower rot. After fruit setting, 800 times of 50% carbendazim wettable powder was used to prevent and control fruit ripening rot. From May to June, for the prevention and control of root rot, you can choose to use 800 times of 95% trichloroisocyanura nitrogen dispersible granules, 400 times of 69% enoyl-manganese-zinc wettable powder or 500 times of 52% methylfrost-manganese-zinc wettable powder. In July, spraying for the prevention and control of brown spot disease can be used with 1 000 times of 70% thiophanate-methyl wettable powder, 2 000 times of 10% difenoconazole water-dispersible granules, and 500 times of 80% mancozeb wettable powder, etc., with an interval of 10 days and 3 times of continuous prevention, which can obtain the ideal control effect. For the prevention and control of red spiders, the control is carried out 3 times a year, respectively in late March, mid-April and mid-August, and the use of pesticides can choose 5 Baumé stone sulfur mixture, 20% pyridafen EC, 20% thiobenone EC, 5% zole difenoxil suspension, etc. In the windless night, collect an appropriate amount of sawdust in the open space of the park, add 20% trichlorfon and mix it evenly, and then ignite it to fill the park with thick smoke, and use the smoke method to control Spodoptera exigua. In addition, the use of phoxanthion irrigation to kill beetles, the use of thiazinone and chlorpyrifos to control mulberry scale and other scale insects, timely spraying of imidacloprid pesticides to control leafhoppers.
3 Summary
To sum up, the prevention and control of kiwifruit should take green plant protection as the main development concept, fully combine the habits of kiwifruit itself, select varieties with strong adaptability, high yield, and good resistance to pests and diseases for cultivation and management, and on the basis of fully ensuring the safety of kiwifruit fruits, take agricultural control, physical control, biological control and drug control and other means to effectively prevent and control kiwifruit diseases and pests, build a perfect green and environmentally friendly prevention and control system, and ensure the realization of agricultural ecological safety. The quality and safety of kiwifruit further enhance the brand image and achieve the purpose of promoting farmers' income and getting rich.