Control of wax scale in planting jujube tree

In recent years, jujube tortoise wax scale spread in our city counties, serious harm, causing jujube tree general weakness, yield significantly reduced, or even no yield. In order to effectively develop the chemical control work of Cerococcus chinensis, we have carried out the experiment of eliminating Cerococcus chinensis for 4 years continuously since 1996, and obtained obvious benefit.

1. Determine the favorable period of spraying to eliminate scale

White wax coats the eggs 4-5 days after hatching and thickens day by day, which is difficult to control with chemicals. Therefore, the most effective period of pesticide to eliminate scale insects is within 3-5 days after the eggs hatch into nymph before the nymph wears wax. However, it is difficult to control the spraying period of this insect because of its large number of eggs, large number of reproduction and long incubation time. In the selection of chemicals should not only have the effect of killing the newly hatched nymph, but also have the effect of killing eggs, and should also have a strong penetration effect on the newly waxed nymph.

In order to determine the most effective period of chemical control of Chinese date turtle wax scale, we set up 9 experimental sites in 8 counties (districts) in 1996 -97 and observed them continuously for two years. It was concluded that the initial incubation period of this insect in our city was July 5-7, the peak period was July 12-15, and the last period was July 19-23. Therefore, the effective period of control should be these three periods.

II. Effect of drugs on treatment

In 1997, we carried out pesticide control tests at each test site during these three periods, using 40% isoamine-thiophos 1000 times and adding auxiliary Happyn 1000 times. 2 plants were fixed at each spot, 5 branches of 10 cm length were randomly selected from the east, west, south, north and upper parts of each plant, and fixed with hanging tags to investigate the number of pests before and after spraying.

The results showed that there were 64 insects per branch on average before spraying, and 2.3 insects per branch after three times of pesticide control, and the insect population density decreased by 96%.

The results showed that the chemicals used to eliminate scale according to the requirements were suitable and effective in both time and chemical selection.

3. Effect of scale control on restoring tree vigor and yield

At the same time of scale control, we selected 4 jujube trees of similar age and tree vigor in each experimental site, 2 trees were sprayed and 2 trees were not sprayed as control, and the number of new jujube heads and permanent second branches and yield were investigated in the second year.

The results showed that there were 103.75 new jujube heads per plant, 96.7% more than 52.75 in the control, 12 permanent secondary branches per jujube head, 58.6% more than 7.75 in the control, and 40.75 kg yield, 162.1% more than 15.55 kg in the control.

The results showed that the pesticide had obvious effect on the restoration of tree vigor and yield in the second year after removing scale.