Control techniques of Diseases and insect pests in Citrus

Citrus belongs to the family Rutaceae, which is sexually fond of warm and humid climate, main diseases and insect pests and control of citrus growth and development. due to the influence of pests or adverse environmental conditions, its normal growth and development is suppressed, metabolism changes, resulting in yield reduction, quality deterioration, and even death, which brings great loss to the economic value of citrus. Seriously affected the economic income of growers, therefore, a clear understanding of the main citrus diseases and insect pests and take effective measures for control is the biggest harvest for growers, let's take a look at the citrus pest control technology!

Citrus Huanglong disease

[harmful symptoms] Citrus Huanglong disease, also known as yellow tip disease, is a plant quarantine object disease in China. Seedlings and young trees die within 1-2 years, and adult trees lose fruiting ability within 2-3 years. In the initial stage, the symptom is the disease on a small number of new shoots of individual plants, mixed with a small amount of yellow shoots in the thick green crown, commonly known as golden flower or chicken head yellow. The leaf on the diseased tip becomes hard and brittle, and the mesophyll turns yellow from the base of the leaf, while the lateral veins of the main vein remain green, with yellow-green mottled, enlarged veins, local cork cracking or uniform yellowing of the whole leaf.

[control technology] ① strictly quarantines and forbids the introduction of seedlings and scions from disease-free areas and disease-free areas. ② should cultivate disease-free seedlings and establish disease-free nurseries. The site should be selected areas free of Huanglong disease and citrus planthopper, and virus-free seedlings should be selected. ③ pest control, timely control of the disease vector citrus planthopper. The diseased plants were removed by ④, the examination was strengthened, and the diseased plants were treated in time.

Citrus canker

[harmful symptoms] Citrus canker is the object of plant quarantine at home and abroad. Seedlings and young trees suffer seriously, resulting in fallen leaves and withered branches, weak tree potential, mild fruit damage with disease scar, reduced quality, heavy fruit drop and reduced yield. The disease is harmful to leaves, branches and fruits. The lesion was needle-sized, yellow and flooded at first, then enlarged into a near-circular spot, raised on both sides of the leaf, corked, rough, grayish brown, crater-like cracking.

[control technology] ① strictly implements quarantine, soaking introduced seedlings and scions with 0.3% ferrous sulfate for 10 minutes. ② strengthens cultivation management, winter pruning and garden cleaning. Do a good job of wiping buds and controlling tips to reduce the incidence of the disease. Apply fertilizer reasonably and control the shoot with fertilizer. ③ spray to protect shoots and fruits, choose 77% copper hydroxide wettable powder, 30% copper oxychloride suspension 800 / 1000 times, 20% dichloroisocyanurate methyl wettable powder 1000 / 1500 times or 20% quinolone wettable powder 1000 / 1500 times.

Citrus scab disease

[harmful symptoms] Citrus scab is mainly harmful to leaves, shoots and fruits, resulting in falling leaves and fruits. The undiseased fruit is small and deformed, the quality becomes worse, and the damaged shoots grow poorly. The disease can only infect the young tissues of leaves, shoots and fruit fields, and the damaged leaves show small water-immersed spots at first, then gradually expand, showing waxy yellow to yellowish brown, with a diameter of 0.3~2.0mm and corkiness.

[prevention and control technology] ① seedling quarantine, the newly built garden introduces seedlings and scions from other places, and carries on quarantine. Scions and seedlings from other places can be soaked in 50% carbendazim wettable powder 800 times and 40% triadimefon carbendazim 800 times wettable powder for 30 minutes. ② strengthened cultivation management, combined with pruning in winter, cut off diseased branches and leaves, collected ground branches and leaves and burned them, and then sprayed on trees and under trees to prevent them. Strengthen the management of fertilizer and water, promote the tidiness of shoots, shorten the tender period of young fruit, and reduce the chance of bacterial infection. ③ chemical spray control, protect tender shoot leaves and young fruits. You can choose 30% copper oxychloride suspension 600x solution, 40% triadimefon carbendazim wettable powder 800x solution or 50% imipramine manganese complex 1000 times solution spray.

Citrus anthracnose

[harmful symptoms] Citrus anthracnose often causes a large number of fallen leaves, withered shoots and fruits of citrus trees, resulting in weakness of trees, decline of products and quality, and even death of branches and plants.

[control technology] ① should strengthen cultivation management, deep ploughing and soil improvement to avoid partial application of nitrogen fertilizer, increase application of organic fertilizer, phosphorus and potassium fertilizer, timely drainage and irrigation, and do a good job in preventing frost and other diseases and pests. ② cleans the garden in winter, cuts off diseased branches, leaves and fruits, removes fallen leaves and diseased fruits, and burns them centrally or deeply. ③ spray control, in spring, summer and autumn shoot tender leaf stage, young fruit stage and fruit expansion stage, choose 25% prochloraz EC, 24% nitrile benzazole suspension, 43% mancozeb suspension 1000 times or 25% bromocyanonitrile EC 500 times 800 times.

Citrus nematode disease

[harmful symptoms] Citrus nematode mainly harms the roots of the plant, causing damage to the plant, causing the decline of the tree potential, and withering and dying of the whole plant. The injured root tissue overgrew due to stimulation, forming nodules of different sizes, few root hairs, small and yellow upper leaves of the diseased plant, crimped leaf margin, withered leaves, withered shoots and even death of the whole plant.