CN105532582A - Indoor bioassay method for bemisia tabaci imagoes - Google Patents

Abstract

The present invention relates to the field of plant protection, and specifically provides an indoor bioassay method for adults of whitefly, which uses the method of placing the adults in a refrigerator at -18°C for 30 seconds, so that the adults of whitefly are frozen for 2-3 minutes, and the operation is simple and convenient. And it can reduce the damage and error caused by humidity and human operation to the tested Bemisia tabaci during the bioassay. Then, the potter spray tower is used as a spraying tool to spray pesticides. The spraying is accurate and can fully simulate the field spraying method. The indoor bioassay method for adult Bemisia tabaci provided by the invention can understand the resistance level and distribution of whitefly whitefly field populations to agents with different action mechanisms, and further guide field medication more scientifically.

Description

A kind of indoor bioassay method of whitefly adults

technical field

The invention belongs to the field of plant protection in agricultural production, in particular to an indoor bioassay method for adults of whitefly bemisia tabaci.

Background technique

Bemisiatabaci (Gennadius) is a polyphagous insect belonging to the family Aleyrodidae of the order Homoptera. It is widely distributed in more than 100 countries and regions, and has harmed more than 600 species of host plants. In addition to directly sucking plant juice and secreting honeydew to cause mildew, whitefly can transmit more than 110 kinds of plant viruses and cause a variety of plant virus diseases. At present, the control of Bemisia tabaci is still dominated by chemical control, but its drug resistance develops rapidly, and a high level of single resistance and cross resistance to commonly used chemical pesticides have been produced.

Pest resistance monitoring is an important basis for effective control of pest resistance. Bioassay is an important technical means for pest resistance monitoring. It can not only reflect which insecticides the pests are resistant to, but also accurately give the degree of resistance, which has important practical significance for timely adjustment of resistance control strategies.

The bioassay techniques of Bemisia tabaci mainly include systemic method, agar moisturizing leaf soaking method, glass bottle medicine film method, yellow viscose card method and so on. Among them, the internal suction method requires operators to have higher skills, so there are not many applications. The agar-moisturizing leaf soaking method can only measure stomach toxicity activity, but not contact activity. The yellow viscose card method solvent is expensive, bulky and complicated to operate. Although the glass bottle drug film method is easy to operate, it can only measure contact toxicity and cannot measure stomach toxicity resistance.

At present, the method for detecting the biological activity of pesticides on whitefly adults is mainly to anesthetize the adults with CO ₂ and then transfer them to the leaves in the insect culture box. This method is not easy to operate, and the concentration and time of releasing CO ₂ are difficult to grasp. The experience of the operator has higher requirements, and a little carelessness may cause non-toxicity death of whitefly adults, which may easily lead to misjudgment of the toxicity level of the tested pesticide.

Contents of the invention

In order to solve the problems existing in the prior art, the object of the present invention is to provide a method for indoor bioassay of whitefly adults. In order to realize the object of the invention, the technical scheme of the present invention is as follows:

A method for indoor bioassay of Bemisia tabaci adults is characterized in that the steps of the method include preparing a plastic insect breeding box, putting test insects in the box, freezing, spraying chemicals, and observing in an artificial climate box.

Further, the method includes the steps of:

①Preparation of pharmaceuticals with different concentration gradients according to the proportion;

② Prepare 1% agar and spread the agar on the bottom of the plastic insect culture box;

③Put the cucumber leaves back on the agar to keep the leaves fresh;

④ Gently pat the adults of Bemisia tabaci into the plastic insect rearing box, quickly seal it with plastic wrap, tie it tightly, and prick several holes with a dissecting needle;

⑤Put the plastic insect culture box containing the whitefly adults in a -18°C refrigerator to freeze the whitefly adults for 2-3 minutes, but there is no obvious effect on the mortality rate;

⑥ Put the plastic insect box in step ⑤ quickly under the potter spray tower to spray the pesticide, then re-seal it with plastic wrap and tie it tightly;

⑦Put step ⑥ plastic insect cages into the artificial climate box, under the conditions of photoperiod 16:8, temperature 27°C, and humidity 70%, respectively raise them for 48 hours and then observe and record the death of Bemisia tabaci in the plastic insect cages , At the same time observe the moldy situation of leaf preservation and synthetic medium every day.

Further, the preparation of the agar needs to add 4 g of calcium nitrate Ca(NO3) ₂ , 0.5 g of potassium dihydrogen phosphate KH ₂ PO ₄ , 0.5 g of magnesium sulfate MgSO ₄ , and 50 mg of streptomycin sulfate to keep the leaves fresh;

Further, the adults were placed in a -18°C refrigerator for 30s;

Further, the pressure and spray dosage of the potter spray tower are respectively 68.9Kpa and 2ml;

The beneficial effect of the present invention is: adopting the method of placing adults in -18 DEG C refrigerator for 30 seconds, making Bemisia tabaci adults frozen for 2-3 minutes, easy to operate, and can reduce the humidity and artificial operation of the bioassay process on the smoke powder for testing. Damage and errors caused by lice. Then the poter spray tower is used as a spraying tool to spray pesticides, which is accurate in spraying and can fully simulate the way of spraying pesticides in the field. The indoor bioassay method for adult Bemisia tabaci provided by the invention can understand the resistance level and distribution of whitefly whitefly field populations to agents with different action mechanisms, and further guide field medication more scientifically.

The technical solution provided by the invention not only ensures the control survival rate of Bemisia tabaci, but also ensures the accuracy of drug application, and is easy to operate, and avoids the influence of uncertain factors on the experimental results in the open external environment, which is consistent with the biological experiment to maintain a single Variable principle.

detailed description

The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

Example 1

Indoor Toxicity Evaluation of Acetamiprid to Bemisia tabaci

1. Research object: Bemisia tabaci adults on cucumber plants in the facility greenhouse.

2. Method: The test agent is acetamiprid preparation with a concentration greater than 20%, and the adults and leaves of Bemisia tabaci are sprayed with the potter spray tower method, and the indoor toxicity test is carried out.

2.1 Preparation and dilution of different concentrations of liquid medicine: on the basis of the pre-test, dilute the Benevir preparation to 6 concentrations with pure water, add 0.1% Trixon-100 to the solution as an emulsifier, and use the same volume of Trixon-100 in clear water For control.

2.2 Selection of leaves for bioassay and preparation of 1% agar: prepare 1% agar containing 4 g of calcium nitrate Ca(NO3) ₂ , 0.5 g of potassium dihydrogen phosphate KH ₂ PO ₄ , 0.5 g of magnesium sulfate MgSO ₄ , and 50 mg of streptomycin sulfate Agar, spread the agar on the bottom of the plastic insectarium. Place the cucumber leaves backside up on the agar.

2.3 Toxicity Determination Selection of Bemisia tabaci for the test: select the adults of Bemisia tabaci on the cucumber leaves in the facility greenhouse, gently pat the adults of Bemisia tabaci into the plastic insect-raising boxes, and put about 20 bemisia in each insect-raising box adults. Quickly seal it with plastic wrap, tie it tightly, and prick several holes with a dissecting needle for ventilation.

2.4 Freezing treatment of test insects: put the plastic insect culture box containing whitefly adults in a -18°C refrigerator to freeze the whitefly adults for 2-3 minutes, but there is no obvious effect on the mortality rate;

2.5 Potter spray tower method to spray Bemisia tabaci adults and leaves: Open the plastic insect culture box frozen in step 2.4, quickly place it under the potter spray tower and spray 2ml of the medicine, the pressure used is 68.9Kpa, and then re-seal with plastic wrap, truss;

2.6 Result inspection and death standard judgment: After 48 hours, check the results, lightly touch the whitefly with a brush, and only one leg moves or does not move at all, which is recorded as death, and the control mortality rate is less than 10% as effective determination. Each concentration was repeated 4 times, and the data was calculated using POLO analysis software to calculate LC ₅₀ . (The results are shown in Table 1).

Table 1 Indoor toxicity test results of acetamiprid to field Bemisia tabaci

As can be seen from table 1 result, utilize bioassay method of the present invention, the mortality rate of control bemisia tabaci adult is less than 10%, illustrates that -18 ℃ processes the method for bemisia tabaci adult 2-3min to the mortality rate of bemisia tabaci adult. Little effect. The used 1% agar containing calcium nitrate Ca(NO3) ₂ , potassium dihydrogen phosphate KH ₂ PO ₄ , magnesium sulfate MgSO ₄ and streptomycin sulfate can effectively maintain the freshness of cucumber leaves for a long time without mold and Rot, this method also has the advantages of simple operation, good repeatability, and accurate results.

Example 2

Evaluating the Toxicity Level of Acetamiprid to Bemisia tabaci by Agar Moisturizing Leaf Soaking Method

1. Research object: Bemisia tabaci adults on cucumber plants in the facility greenhouse.

2. Method: The test agent is acetamiprid preparation with a concentration greater than 20%, and the leaves are treated with agar moisturizing soaking method to feed the adults of Bemisia tabaci, and the toxicity test is carried out indoors.

2.1 Preparation and dilution of different concentrations of liquid medicine: on the basis of the pre-test, dilute the Benevir preparation to 6 concentrations with pure water, add 0.1% Trixon-100 to the solution as an emulsifier, and use the same volume of Trixon-100 in clear water For control.

2.2 Selection of bioassay leaves and preparation of 1% agar: prepare 1% agar, spread the agar on the bottom of the plastic insect culture box. The cucumber leaves were dipped in various concentrations of medicinal solutions for 10 seconds, dried, and placed on the agar with the back side up.

2.3 Toxicity determination Selection of Bemisia tabaci for the test: select the adults of Bemisia tabaci on the cucumber leaves in the facility greenhouse, anesthetize the female adults of Bemisia tabaci with _CO2 for a short time, and transfer them to the small round leaves in the insect breeding box. 20-30 female adults in the insect breeding box, quickly sealed with plastic wrap, tied tightly, and pricked several holes with dissecting needles for ventilation. When Bemisia tabaci recovered from anesthesia, the insect rearing box was placed upside down in an incubator at (25±1)°C, relative humidity 65%, and light 14:10 (L:D).

2.4 Result inspection and death standard judgment: After 48 hours, check the results, lightly touch the whitefly with a brush, and record it as dead if only one leg moves or does not move at all, and the control mortality rate is less than 10% as effective determination. Each concentration was repeated 4 times, and the data was calculated using POLO analysis software to calculate LC ₅₀ . (The results are shown in Table 1).

Example ₂ shows that the current method of anesthetizing adults with CO and transferring them to the leaves in the insect box has relatively large operating errors, and it is difficult to grasp the concentration and time of releasing _CO . This method is subject to the experience and techniques of operators. The limitation is relatively large, and there is a problem of high mortality rate in the control group. In addition, due to the use of the leaf dipping method, only the stomach poisoning activity of the drug can be evaluated, and the drug solution is not sprayed on the surface of the insect body, lacking the evaluation of the contact effect of the drug, and the experimental results cannot be accurately judged.

Although the present invention has been described in detail with general descriptions and specific embodiments above, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. Therefore, the modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the protection scope of the present invention.

Claims (4)

1. a method for Bemisia tabaci adults indoor bioassay, is characterized in that, described method step comprises preparing plastic insect box, in box, put into examination worm, freezing, spray medicament, observe at climatic cabinate.

2. method according to claim 1, is characterized in that, described method comprises the steps: 1. to be laid in bottom plastics insect box by the agar of 1%, is placed in upward on agar at the cucumber leaves back side, to keep blade fresh; 2. Bemisia tabaci adults to be beated in gently plastics insect box, rapidly with preservative film sealing, tighten, with dissection pinprick number hole; 3. the plastics insect box that Bemisia tabaci adults is housed is placed in-18 DEG C of refrigerators, Bemisia tabaci adults 2-3min numb with cold is not but had a significant effect to lethality; 4. by step 3. plastics insect box spray medicament under being placed in rapidly potter spray tower, then again seal with preservative film, tighten; 5. by step 4. plastics insect box put into climatic cabinate, at photoperiod 16:8, temperature 27 DEG C, under humidity 70% condition, raise after 48h the survival rate of observing, recording Bemisia tabaci in plastics insect box, observe the mouldy situation of the fresh-keeping and synthetic medium of blade simultaneously every day.

3. method according to claim 2, is characterized in that, the preparation of described agar need add nitrate of lime Ca (NO3) ₂4g, potassium dihydrogen phosphate KH ₂pO ₄0.5g, magnesium sulfate MgSO ₄0.5g, streptomycin sulphate 50mg think that blade is fresh-keeping.

4. method according to claim 2, is characterized in that, described adult is placed in 30s in-18 DEG C of refrigerators;

Method according to claim 2, is characterized in that, pressure and the sprayed dose of described potter spray tower are respectively 68.9Kpa and 2ml.