Citrus Red spider mites is a important pest of Citrus and a headache for all citrus growers, especially in the provinces like Guangxi. The annual average temperature is high and the red spider mites is harmful throughout the year. But, since already spent too much to control it, why the efficiency is still unsatisfied?
Red spider mites is also called Panonychus citri. It’s the main harmful mites for citrus regions. The adult, nymph and larva pierce and suck the juices of the leaves, tender shoots and fruits. The infected leaves show countless gray spots and the leaves will turn gray in severe case.
WHy it’s so difficult to be controlled?
1: Super breeding ability(20 generations per year)
It has super breeding ability and can have 12-20 generations per rear. Usually there are 2 peaks per year. One is from April to June when there are rich nutrition in the tender shoots and young leaves. Another is from September to October when there are new shoots.
One generation need 20-40 days. The female adults canlive more than 50 days in winter and 10 days in summer.It’s sexual reproduction, but only female can also breed. One female can spawn 35 eggs per day.
2: No one acaricide can kill eggs, larva, nymph and adult at the same time
Due to its super breeding ability, there can be 4 generations at one leaf. There’s not a acaricide can kill 4 generations together.
3: They like to live at the back of leaves. So normal spraying cann’t kill them thoroughly.
4: Stronger and stronger resistance ti the acaricides
Repeated use of one acaricide for years cause strong resistance’ rising. According to the determination, its resistance to Pyridaben has rose 25 time.
For citrus, it should apply lots of pesticides, especially copper fungicides which can stimulate mites’ breeding and larva’s growth. Pyrethroid pesticides, same. The main manifestations are the higher survival rate, more egg production, and higher hatching rate, which can reach 10% to 25%. The result is: more application of pesticides, more red spider mites.
How to control red spider mites scientifically?
1: Control in the peak period of breeding
High temperature and rain can inhibit red spider mites’ breeding. There are 2 peaks of breeding every year. Oneisfrom April ro June, another is from September to October. So do the preparation well before and at end of the peak period and it will effectively lift the control effect.
2: Use mineral oil preferentially
Mineral oil+Abamectin is the top choice in some places. Because mineral oil can control the red spider mites by blocking up the stigma and will not rise the resistance. It can also control the scale insects and sooty molds, etc.
3: Apply the pesticides reasonably
Sprouting - Initial flowering stage(March to April): Etoxazole 20%+Abamectin 4% SC
Flowering stage - physiological fruit-falling period(May to June) Abamectin 1.8% EC+Spirodiclofen 24% SC
Summer shoots spouting(July to August): Abamectin 1.8% EC mix Azocyclotin+Etoxazole 30% SC(temperature should be lower than 32 degree and spray in the afternoon)
Fruit developing period - Harvest period(September-October): Abamectin 1.8% EC+Spirodiclofen 24% SC or Bifenazate+Etoxazole 30% SC
Orchard clearing period(December-February): Propargite 40% EC+Mineral oil