Occurrence and Control of Pinctada
Dioryctria sylvestrella (Ratzeburg) is a lepidopteran, moth family. It is distributed in Heilongjiang, Liaoning, Hebei and Jiangsu provinces. It mainly injures cones, young shoots, and cadres of young trees of Pinus koraiensis and Pinus koraiensis, causing seeds. Production declines and quality is poor.
The larvae bore holes in the pine cones and shoots of the young shoots, causing the dead heads to die, the side shoots to replace the main shoots, and to form bifurcations; harming the base of the top buds of the shoots, causing the top buds to die, and the new shoots to fail in the next year. Pumping, seriously affecting the normal growth of Korean pine and red pine.
Morphological characteristics
The adult body is 15mm in length and 28mm in wingspan, and the filamentous antenna is dense brown short hair. Silver gray front wing with black and white scales, fin-based scales white; sub-baseline and inner horizontal lines connected at the base of its trailing edge and covered with black and white scales, horizontal and outer transverse lines white corrugated, inner and middle horizontal lines The trailing edge was covered by brown scales, and the white kidney-shaped plaque was diagonally obtrusive behind the lateral line at the end of a white scale area. The black outer edge lined the inside with white scales and gray hair. The hind wings are greyish white. The back of the abdomen is gray-brown and white, silver and copper scales. Black feet, black and white scales.
Egg oval, about 0.7mm long, dark red.
The larvae have a body length of 21 mm and a head width of 1.2 mm. Grayish brown or grayish black. Head dark brown, chest, abdomen sallow and bright, growing bristles in a circle; pronotum back black, back midline gray, hair in front of the chest valve hair bristles, 3 pairs of black tufts of each section, the back midline of the 4 One hair bristles each had one set of bristles, and under the valve line the hair bristles had two short bristles that were short before birth and then long. Gastropoda hook 2 order ring.
The ellipse is long, 15mm long and 3mm wide. Yellowish brown, 6 hips without hips.
The law of occurrence occurs in Heilongjiang for one generation and winters as larvae. Activities began in April. In late May, larvae began to mature. Adults emerged from mid-June to early July, and spawned in late June. In early July, larvae hatched and endangered wintering in October.
In April, the temperature rose, and the larvae began to move, harming the verticillate branches and cones at the base of the shoot. When the insects were damaged, they all invaded from the cuts of the pruning branches, mechanical collisions, lesions of the pine and rust, and the like. The formation of neoplasia; damage to the cone from the cone in the lower part of the invasion, the site of damage with white transparent turpentine and brown insect feces. In late May, the mature larvae feed on the shoot xylem, bite the diurnal chamber and the feathering hole above it, and stick the silky wood chips to seal the feathering hole. 17 days. In mid-June, the adult began to emerge, and the emergence period was about 20 days. In late June, it was the mating and spawning period. July larvae damage, at the end of July and early August, the affected cones flowed a lot of fat, causing the larvae to be visibly dead and viscous death rate up to 74%; if there were several consecutive rainfalls, the fat loss was stopped. Heavily harmed. In October, the temperature dropped and the larvae overwintered under the tumours.
The insects liked to grow light in the broad-leaved trees with a canopy density of 0.7. The young trees were not harmed; the canopy density was afforested at 0.3, and the damage rate of the young Korean pine was 0.1%; the damage was increased when the light transmittance increased. Transmitted light when the rate of 45%.
Control methods
(1) Strengthen forest area management.
In combination with tending, a young forest is created under the forest canopy, and a certain number of broad-leaved trees are reserved along with the growth of the young forest to improve canopy density and reduce damage. In the winter and spring, the nursery, young forest, and scattered trees are surveyed, and it is found that the locust infestation has been cut off immediately. And pay attention to the removal of overwhelming insects, concentrated burning.
(2) According to adult phototaxis, black light traps are set.
(3) Chemical control.
For young instar larvae, 90% trichlorfon crystals or 50% phoxim EC may be sprayed 1000-1500 times, or 50% chlorpyrifos EC, or 50% dichlorvos EC, or 50% Phosphate EC 1000 times.
Commonly used trichlorfon, phoxim, safrole, dichlorvos, phosphorus rubber
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