The Latest Technical Methods and Tutorial for Citrus Pest and Disease Control
Citrus belongs to the genus Citrus under the Rutaceae family, and prefers a warm and humid climate. Main pests and diseases and their control: During the growth and development of citrus, when the influence of harmful organisms or adverse environmental conditions exceeds its adaptive capacity, its normal growth and development are inhibited, its metabolism changes, leading to reduced yield, deteriorated quality, and even death. This brings huge losses to the economic value of citrus and seriously affects the economic income of growers. For this reason, clearly understanding the main pests and diseases of citrus and taking effective measures for prevention and control is the greatest gain for growers. Below, let us take a look at citrus pest and disease control techniques!
Citrus Huanglongbing
[Damage symptoms] Citrus Huanglongbing, also known as yellow shoot disease, is a plant quarantine disease in China. After nursery stock and young trees are affected, they die within 1~2 years; after adult trees are affected, they lose fruiting capacity within 2~3 years. Its symptoms initially appear on a few new shoots of individual plants, with a small number of yellow shoots mixed into the dark green canopy, commonly known as "inserted golden flowers" or "chicken-head yellow." The leaves on diseased shoots become hard and brittle. The mesophyll begins to turn yellow from the base of the leaf while the midrib and lateral veins remain green, showing a mottled pattern of alternating yellow and green. The veins swell, and localized areas become suberized and cracked, or the entire leaf turns uniformly yellow.
[Control techniques] 1. Strict quarantine: prohibit new areas and disease-free areas from introducing nursery stock and scions from diseased areas. 2. Cultivate disease-free nursery stock: establish disease-free nurseries, choosing sites in areas where Huanglongbing and the Asian citrus psyllid do not occur, and select virus-free nursery stock. 3. Pest control: promptly control the disease-transmitting vector, the Asian citrus psyllid. 4. Remove diseased plants: strengthen inspection and promptly deal with diseased plants.
Citrus Canker
[Damage symptoms] Citrus canker is a plant quarantine object at home and abroad. Nursery stock and young trees suffer severe damage, causing leaf drop and dead branches, and weakening tree vigor. Affected fruit may carry disease scars in mild cases, reducing quality, or drop in severe cases, reducing yield. This disease damages leaves, twigs, and fruit. The lesions are initially needle-head sized, yellow, and water-soaked, then expand into nearly circular lesions, raised on both the front and back of the leaf, suberized, with a rough surface, grayish-brown, and cracked in a volcano-like pattern.
[Control techniques] 1. Strictly implement quarantine: for introduced nursery stock and scions, soak in 0.3% ferrous sulfate for 10 minutes. 2. Strengthen cultivation management: winter pruning and orchard cleaning. Do well in bud removal and shoot control to reduce disease incidence. Apply fertilizer reasonably and use fertilizer to control shoots. 3. Spray chemicals to protect shoots and fruit: choose 77% copper hydroxide wettable powder, 30% copper oxychloride suspension 800~1000 times dilution, 20% dichloroisocyanuric acid wettable powder 1000~1500 times dilution, or 20% quinolinone wettable powder 1000~1500 times dilution for spraying.
Citrus Scab
[Damage symptoms] Citrus scab mainly damages leaves, new shoots, and fruit, causing leaf drop and fruit drop. Diseased fruit that does not drop is small and deformed, with deteriorated quality, and affected new shoots grow poorly. This disease can only infect young and tender tissues of leaves, shoots, and fruit. Affected leaves initially show water-soaked small spots, which gradually expand, becoming wax-yellow to yellow-brown, 0.3~2.0 mm in diameter, and suberized.
[Control techniques] 1. Nursery stock quarantine: for newly built orchards, quarantine nursery stock and scions introduced from other places. Scions and nursery stock from other places can be soaked for 30 minutes in 50% benomyl wettable powder 800 times dilution or 40% triadimefon-carbendazim wettable powder 800 times dilution. 2. Strengthen cultivation management: in winter, combine with pruning, cut off diseased branches and leaves, collect fallen branches and leaves on the ground and burn them together, and immediately spray the tree and the ground for prevention. Strengthen fertilizer and water management to promote neat shoot emergence, shorten the tender stage of young fruit, and reduce opportunities for pathogen infection. 3. Chemical spray control: protect tender shoots, leaves, and young fruit. You may choose 30% copper oxychloride suspension 600 times dilution, 40% triadimefon-carbendazim wettable powder 800 times dilution, or 50% prochloraz-manganese complex 1000 times dilution for spraying.
Citrus Anthracnose
[Damage symptoms] Citrus anthracnose often causes large amounts of leaf drop, shoot dieback, and fruit drop in citrus trees, leading to weakened tree vigor, reduced product and quality, and even death of branches and plants.
[Control techniques] 1. Strengthen cultivation management: deep plowing and soil improvement, avoid partial application of nitrogen fertilizer, increase application of organic fertilizer and phosphorus and potassium fertilizers, drain and irrigate in time, and do well in freeze protection and prevention of other pests and diseases. 2. Winter orchard cleaning: cut off diseased and dead branches and leaves and mummified fruit, clear fallen leaves and diseased fruit on the ground, and burn or deeply bury them in a centralized manner. 3. Chemical spray control: spray during the tender leaf stages of spring, summer, and autumn shoots, the young fruit stage, and the fruit expansion stage. Choose 25% prochloraz emulsifiable concentrate, 24% fenbuconazole suspension, 43% mancozeb suspension 1000 times dilution, or 25% bromothalonil emulsifiable concentrate 500~800 times dilution for spraying.