Occurrence and damage characteristics of orange fruit fly in persimmon orchard and key points of prevention and control techniques

Occurrence and damage characteristics of orange fruit fly in persimmon orchard and key points of prevention and control techniques

1 the basic situation of orange small fruit fly

Orange small fruit fly (Bactrocera dorsalis Hendel), also known as citrus small fruit fly, oriental fruit fly, fruit maggot, etc., belongs to Diptera fruit flies and fruit flies. It is a very harmful omnivorous pest. It is an important quarantine pest against more than 250 kinds of fruits and vegetables, such as citrus, persimmon, carambola, figs, peaches, plums and so on. The description of the morphological characteristics of orange fruit fly needs to be analyzed from three stages: adult, egg and pupa. The main results are as follows: 1) in the adult stage, the female adult is 6-8 mm long, with a wingspan of about 16 mm, dark black. The forechest dorsal plate is dark brown with 2 yellow longitudinal lines. The abdomen is composed of 5 segments, yellow, with T-shaped black spots. The body length of male adults is 0.7-0.8 mm. 2) in the egg stage, the color is light yellow, the shape is similar to the kidney shape, and the length is 1.52 to 1.60 mm. 3) pupa stage, yellowish brown, oval, with a length of 8.0 to 10.0 mm. Figure 1 shows the adult orange fruit fly.

2 the damage characteristics, occurrence regularity and causes of orange small fruit fly

2.1 damage characteristics

Usually, the adults lay eggs in the persimmon fruit, and the larvae gather in the fruit to feed on the flesh. After persimmon was damaged by insect pests, the internal tissue of persimmon changed gradually, and the respiration was enhanced to a certain extent, which led to the phenomenon that the fruit was not ripe but the pericarp was yellow first, and there was a little red in the yellow. In addition, the pedicel of the insect fruit is separated, the fruit falls in advance, the larval fruit falls to the ground, and continues to rely on the survival and development of the fruit. After eating the fruit meat into paste, the fruit fester [2]. After the fruit is damaged, it is easy to fall off in the early stage, and then reduce the yield, at the same time, the quality of the fruit will also be greatly affected. The serious persimmon orchard production of some orange small fruit flies is faced with huge losses.

Fig. 1 small orange fruit fly

2.2 occurrence regularity

In recent years, through fixed-point system monitoring, the adult of orange fruit fly began to appear in persimmon orchard in Pingle county from late May of the following year, and the population was low from June to August. The adult began to increase from the first ten days of September, the peak period of adult occurrence was from the first ten days of October to late November, the number of adults decreased sharply in the middle of December, and no adult was found from January to April. There are 3 to 4 generations every year, and the generations overlap and are not easy to distinguish. After Eclosion, the adult can mate and lay eggs only after a period of sexual maturity. when laying eggs, the adult relies on the egg organ needle in the tail to pierce the pericarp and then lay eggs in it. The number of eggs laid by adults is 5-10 eggs per time, and 200-400 eggs a year. The egg stage lasts 1-3 days in summer and autumn and 13-20 days in winter. After hatching, the larvae feed in the fruit. Causing the fruit to rot and fall off. After 7 days and 15 days, the mature larvae pierced and bounced to the ground and pupated.

2.3 causes of occurrence

Judging from the current damage of orange small fruit fly, the factors leading to its occurrence mainly include the following aspects. 1) wide host. It can harm more than 250 kinds of fruits and vegetables, such as guava, carambola, citrus, persimmon, melon and so on. 2) there are some problems in the management of persimmon orchard. The economic benefit of persimmon is lower than that of other fruits, which affects the enthusiasm of farmers in the management of orange fruit flies. 3) it is difficult to rule by unified defense in a large area. At present, melons, fruits and vegetables in Pingle County are still mainly planted in a small area, so it is difficult to unify control measures, resulting in low control effect. 4) the means of prevention and control are relatively backward. The degree of attention to the prevention of orange small fruit fly is not high, usually after the treatment, the lack of corresponding preventive measures.

(3) Prevention and control measures of orange fruit fly.

Adhere to the plant protection policy of "prevention first, comprehensive control", implement the concept of "public plant protection, green plant protection, and scientific plant protection", and implement the working mechanism of "government leadership, territorial responsibility, joint prevention and control, and unified prevention and control". We will vigorously promote the green prevention and control technology of specialization, joint prevention and control, group control and group control, and control the overall damage rate of small fruit flies in persimmon orchards to less than 5% [3].

3.1 do a good job in agricultural prevention and control

3.1.1 dig deep into the soil

Combined with clearing the garden in winter, ploughing the soil once, and burying the overwintering pupae deeply, so that the overwintering pupae can not be feathered, this measure can significantly reduce the source of overwintering insects and reduce the occurrence of the first generation pests in the coming year.

3.1.2 raising chickens

By raising chickens, the eggs and larvae in the fallen fruit can be pecked, and the adults of orange small fruit fly can be eaten, which is the most direct and effective way to reduce the population density.

3.1.3 pick up fallen fruit and insect fruit

Because the eggs and larvae are in the fruit, picking up the fallen fruit and insect fruit is one of the effective methods to reduce the population density. Pick up the fallen fruit and insect fruit every 5-7 days, bury the fallen fruit and insect fruit deeply or compost them into fertilizer through corresponding measures.

3.1.4 timely and multiple harvesting in batches

The fruits with early maturity and high quality are vulnerable to orange fruit flies. Therefore, it should be harvested in batches at the right time to prevent the fruit from overripe and rotten.

3.2 physical control

3.2. 1 hanging vibrating frequency anti-insect lamp

Orange small fruit fly has phototaxis, and a vibrating frequency anti-insect lamp is hung every 2.67 hm2 to control other pests.

3.2.2 Yellow board trap

When the damage of adults was first found, 20-30 pieces of yellow board / hm2 were placed for seducing and killing.

3.2.3 trapping and killing with sweet and sour solution

According to the biological characteristics that the adult orange fruit fly needs a lot of supplementary nutrition before spawning, the sweet and sour medicine solution was prepared according to 1000g brown sugar, 200g edible vinegar, 100g 15% chlorpyrifos and water for 30 kg.

3.2.4 sexual trapping and killing adults

Attractant control is a very small orange fruit fly control measure gradually used on a large scale in recent years, which has been widely recognized in the industry. There are two kinds of attractants: 1) Food attractants, using the fruit fruit fly trap produced by Hubei Gu Ruite Biotechnology Co., Ltd., spraying 10 points every 667 m2 can trap and kill both male and female adults at the same time. 2) sexual attractants, 3-5 fruit fly traps per 667 m2 to trap and kill males, reduce mating of orange fruit flies, reduce the number of eggs laid by females, and reduce the damage of the next generation of larvae.

3.3 Chemical prevention and control measures

Orange small fruit fly has strong ability of short-range migration, and the effect of chemical spraying is not very ideal, but when the adult population density of orange small fruit fly in persimmon orchard is high, the effect of agricultural control and physical control is limited. In the peak period of adults, the timely use of chemical pesticides combined with other control measures can effectively reduce the population density and greatly reduce the damage. Chemicals can choose 80% dichlorvos EC or 90% crystal trichlorfon 800 ~ 1000 times or 48% chlorpyrifos EC 1500 × 2000 times spray crown and weeds to kill some adults, the best time to apply before 9:00.

Through the observation of persimmon garden, according to the characteristics of adults of orange small fruit fly outside the fruit, the growth and decline of eggs and larvae in the fruit and the growth and decline law of orange small fruit fly, it is difficult to achieve the ideal control effect by using drugs in a small area or using some control techniques alone. Only long-term unified use of drugs in a large area can effectively control the harm of orange small fruit flies to persimmon orchards.