1) Insect pests
i. Red spider of orange: it’s the most dangerous insect pest that affects orange of our country, mainly damaging the leaves, branch tips and fruits of orange. When the leaves and fruits are severely damaged, they will turn into hoar and dim, and finally turned withered and yellow, and fall off. April—June and September—November are the fastigium.
a. Clean the orchard in spring. Cut off the withered branches and branches with disease or pests. Get rid of the weeds in the orchard. Before the fruit trees sprout, the following pesticides can be applied: 0.8—1.0 Baumé degree lime sulfate, gum resin compound 8—12 times diluent or 20% Miejie WP 40—50 times diluent.
b. From sprouting to florescence: 0.3—0.5 Baumé degree LSSS, 5% hexythiazox oil concentrate/WP 1000—1500 times diluent, 10% benzoximate oil concentrate 1500—2000 times diluent or 50% trithion 1200—1500 times diluent.
c. Other seasons: 20% dicofol 1000 times diluent, or azocyclotin, fenbutatin oxide 1500—1800 times diluent, 5% Nissorun 2000 times diluent, 10% clofentezine 1000—1500 times diluent, 20% pyridaben 3000—4000 times diluent, 73% Comite 1500—2000 times diluent, 50% bromopropylate 1500—2000 times diluent.
d. Protect the natural enemies and apply pesticides appropriately. Carry out healthy cultivation. Protect and utilize such natural enemies as mite destroyer, predatory mite, Scolothrips Priesner, lacewing fly, Entomophthorale, etc.
ii. Rust mite: It’s a main insect pest spreading throughout the orange planting areas of our country. The larvae and nymphae throng on the branches, leaves and fruits of orange to cause damage. The affected seed capsule or leaves turn into dark brown. The major onset is from July to September.
a. Optimum period of prevention and control: Mid may to October.
b. Agricultural prevention and control: In high-temperature and dry season, irrigate to fight the drought. Apply organic rotten and ripe fertilizer to improve the eco-condition of orchard and increase the pest-resistant of the tree. Clean the orchard in winter. Cut off withered and sick branches. Paste limewater on the tree trunk to eliminate the source of insect pests that live through winter.
c. Chemical prevention and control: Apply LSSS and 0.3—0.4 degree bordeaux liquid for 1—2 times every month (the concentration can be a bit lower when the temperature is high and the sun is burning), the dosage should not be too heavy to avoid injury. Or 50% Cyhexatin WP 3000 times diluent, 65% zineb 600—800 times diluent, 30% MTMC 600 times diluent, 50% ethion 1000—1500 times diluent.
iii. Leaf miner moth: The insect pest arises throughout the orange planting areas of our country. The larvae hide under the epidermis of tender leaves, branches and young fruits to cause damage. There are 9—15 generations in one year. The pupae and ole larvae live through winter under the epidermis of tender leaves of late autumn shoot and winter shoot. The onset is from early May, and the fastigium is from July to September. The summer shoot is lightly damaged, while the autumn and winter shoots are heavily damaged.
a. Agricultural prevention and control: Cut off and burn the infected branches and shoots when the orchard is cleared in winter. Remove summer shoot and early autumn shoot as much as possible. Strengthen the management of fertilizers and water to make the new shoots grow simultaneously.
b. Pesticide prevention and control: Apply 1% or 1.8 Abamecthin oil concentrate 2500—4000 times diluent, 3% acetamiprid oil concentrate 1000—2000 times diluent, 80% ddvp oil concentrate 800 times diluent, 40% Dimethoate oil concentrate 1200 times diluent, 20% diflubenzuron SC 1000—1500 times diluent, 5% chlorfluazuron oil concentrate 1500—2000 times diluent or pyrethrin pesticides 2000—6000 times diluent, etc.
c. Protect natural enemies: protect and utilize the natural enemies such as parasitic wasp.
i. Citrus yellow shoot: The disease happens in most of the orange planting areas. It’s a main plant disease of orange in our country. The disease can cause acres of orange trees to die.
The Citrus yellow shoot should mainly be prevented.
a. Strictly apply the quarantine system to prevent sick saplings and sick spikes from entering the non-disease district and new plant district.
b. Prevent and control the Diaphorina citri: Murraya paniculata is the host of plant louse. Therefore, Murraya paniculata should not be used as green fence in the orange orchard. If Murraya paniculata has been planted, it should be stubbed immediately. The plant louse mainly causes damage to the new shoots and tender leaves. Therefore, in spring and autumn when the fruit trees are shooting, the plant louse should be prevented and controlled. In summer, bud-picking and shoot-picking should be applied. In winter, the plant louses that live through winter in the back of the leaves should be eliminated when the orchard is cleaned.
c. Stub the sick trees to eliminate the source of infection. The pathogen doesn’t spread evenly in the tree, and its latent period differs. When sick trees are detected, the whole tree should be stubbed and burned. New orange trees should be planted more than one year later, and should not be planted at the same place as the original sick tree.
d. Strengthen the management of orchard and enhance the tree vigor.
ii. Corky scab: Corky scab of orange is a common disease in mid and northern subtropical areas of our country. It happens throughout Zhenjiang, Fujian, Taiwan, Sichuan, Jiangxi, Yunnan, Guizhou, Guangxi, Guangdong, etc. The infected leaves will fall off. The infected branches and shoots don’t grow well. The infected fruits tend to fall off, or be small and freaky with low quality.
a. Clear the orchard in winter. Cut off and burn the sick leaves and branches. Apply 10—15 times resin wash or 0.8—1 Baumé degree calcium polysulphides for 1—2 times. This is to ensure strong tree vigor, make the new shoot sprout simultaneously, and improve the disease-resistance of the tree.
c. When setting up the orchard, choose non-disease saplings to prevent the pathogen.
d. Pesticide Prevention and control: The key period is when the leaves and fruits are yound. When spring shoots sprout, apply pesticides to protect the spring shoots until the length of the bud reaches 2mm. When 2/3 of the flowers wither, apply pesticides to protect the young fruit. The following pesticides can be used: 75% chlorthalonil WP 500—800 times diluent, 50% Duomeiqing WP 800—1000 times diluent, 77% Kocide 2000 type 800 times diluent, 80% Bibei WP 400—600 times diluent, 65% diethofencarb WP 1000—1200 times diluent. The spray times should be decided on the state of illness. Usually spray once for every 10—15 days.
iii. Citrus anthracnose
Citrus anthracnose happens throughout the orange planting areas. It can cause the leaves to fall off, the branches and shoots to wither, the limb to craze and the fruit to rot away.
a. Strengthen cultivation management. The management of orchard should be strengthened to improve the disease resistance of the tree. Enlarge the pit, dig deeply, plant green manures, add organic fertilizers, apply phosphorus fertilizer and potassium fertilizer, and supply microelement fertilizers. Draining and irrigation should be applied in time. Pruning should be paid attention. And prevention and control of other plant diseases and insect pests should be applied in time. Next, clear the orchard in winter. Cut off the sick branches, shoots and fruits. Remove the withered leaves, fallen leaves and sick fruits on the ground to reduce the source of pathogen.
b. Pesticide prevention and control. Pesticides should be applied once in the shooting stage of spring, summer, autumn and winter respectively. Spray the pesticides to protect the tree on the early stage of onset to reduce or stop the disease from infecting. Common antiseptics can prevent the conidiophore of pathogen from bourgeoning, such as: 0.5:0.5:100 bordeaux liquid, 77% Kocide WP 500—600 times diluent, 0.3 Baumé degree calcium polysulphides, 70% thiophanate methyl WP or 50% carbendazim WP 600—1000 times diluent.
Technology support: National Agro-tech Extension and Service Centre