CN108967421B - Liquid attractant for fruit flies, preparation method and application thereof - Google Patents

Abstract

The invention provides a liquid attractant for fruit flies, which comprises the following raw materials in parts by weight: 10-60 parts of protein, 2-15 parts of thickening agent and 30-70 parts of water-soluble alcohol. The attractant uses water soluble alcohol as the liquid base instead of water, and the protein liquid mixture based on water soluble alcohol has physical and microbiological stability, and can be thickened rapidly when water is added, so that the 'overnight waiting' before using is not needed.

Description

Liquid attractant for fruit flies, preparation method and application thereof

Technical Field

The invention belongs to the technical field of agriculture, and particularly relates to a liquid attractant for fruit flies and a preparation method thereof.

Background

Drosophila trypetid is the major fruit pest in china, southeast asia, australia, hawaii, middle east and africa. These include Bactrocera dorsalis, Bactrocera cucurbitae (Bactrocera cucurbitae), Bactrocera kunmenbergi (Bactrocera tryoni), Bactrocera minax (Bactrocera minax), and Bactrocera persicae (Bactrocera zonata), among others. Ceratitis fruit flies, particularly medfly (ceratitis capitata), are the major fruit pests in southern europe, northern europe and sub-saharan africa, western australia, mexico and hawaii. The fruit flies in the genus drosophila are pests of north american cherries and apples. Fruit flies of the genus drosophila in the fruit are the major pests of fruits in mexico, central and south america. All these fruit flies belong to the subfamily fruit flies. Female fruit flies in this subfamily have a strong driving force to find protein sources and they are required for ovarian development. After they are full, they are able to mate and lay eggs. Male fruit flies are also attracted to such protein sources.

Protein-based sprayable attractants have long been used as a means of controlling drosophila and cercospora in combination with insecticides. The protein source typically comprises yeast autolysate (residue from the beer manufacturing process), but may optionally also be made of other inexpensive proteinaceous materials. These protein spray attractants typically consist of 50% solids present in water. They are generally not microbiologically stable and do not have a long shelf life. Both male and female fruit flies are attracted to such protein attractants. When in use, the attractant is added with the insecticide to achieve the effect of killing the fruit flies.

Australian studies have shown that protein bait formulations using water-soluble gelling agents (such as guar or xanthan gum) are more effective than protein bait formulations without such gelling agents. Xanthan and guar gums are typical dry powder thickeners that are insoluble in water soluble alcohols but soluble in water.

These gelling and thickening agents are typically present in concentrations of 0.25% to 0.5% in the spray attractant applied by the farmer. A typical drosophila attractant is a water-based concentrated liquid containing about 50% solids. In use, these attractants are typically diluted to a concentration of 2.5% to 5.0%. At present, all the fruit fly protein attractants on the market are water-based and do not contain any thickening agent, and if the farmers wish to add the thickening agent, the thickening agent needs to be diluted and added one day ahead of time when using. This is because the water-based fruit fly protein attractant cannot be diluted for use when purchased by farmers if an effective concentration of thickener is added in advance. In addition to being unstable and having a short shelf life, the water-based fruit fly protein attractant on the market at present is inconvenient for farmers to use if a thickening agent needs to be added.

However, if the thickener is added directly to the protein attractant, it tends to cake and cause clogging at the spray head. The solution to this problem is usually to mix water and thickener the day before application by the farmer and wait for the mixture to thicken before spraying, and then add the protein concentrate and insecticide to the mixed viscous solution before spraying, and this attractant spray can only be applied without rain because it is easily washed out in the rain.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a liquid attractant for fruit flies, a preparation method and application thereof. The attractant uses water soluble alcohol as the liquid base instead of water, and the protein liquid mixture based on water soluble alcohol has physical and microbiological stability, and can be thickened rapidly when water is added, so that the 'overnight waiting' before using is not needed.

The technical scheme of the invention is as follows: the liquid attractant for the fruit flies comprises the following components in parts by weight:

10-60 parts of protein, 2-15 parts of thickening agent and 30-70 parts of water-soluble alcohol.

The protein is selected from one or more of yeast powder, soybean powder, skimmed milk powder, etc., preferably vegetable protein yeast powder or soybean powder, preferably 40-60 parts.

The thickening agent is soluble in water but not soluble in water-soluble alcohol, and if the thickening agent soluble in alcohol is adopted, the thickening agent is similar to the water aqua described in the background art, and cannot be diluted by water after being bought by farmers.

Such thickeners include, but are not limited to xanthan gum, guar gum, hydroxypropyl guar gum, ethyl cellulose, methyl cellulose, carboxymethyl cellulose, hydroxypropyl methyl cellulose, carageenan, starch, gelatin, pectin, sodium alginate, potassium alginate, tara gum, carob gum.

The preparation method of the fruit fly liquid attractant sequentially comprises the following steps:

(1) the protein and the thickening agent are mixed evenly,

(2) then adding the mixture into water-soluble alcohol, and stirring to form the attractant gel for the fruit flies.

When the fruit fly liquid attractant is used, an insecticide is required to be added, and the insecticide is preferably malathion, thiamethoxam, acetamiprid, dinotefuran, imidacloprid, thiacloprid, clothianidin, deltamethrin, cypermethrin, cyhalothrin, spinosad, spinetoram, abamectin, emamectin benzoate, chlorpyrifos, trichlorfon and the like. The fruit fly bait liquid attractant needs to be diluted by water or an aqueous solution of an insecticide when in use, the viscosity can be quickly increased after dilution, and meanwhile, the fruit fly bait liquid attractant can still be sprayed, the weight concentration of the fruit fly liquid attractant in the aqueous solution of the insecticide is 2-15%, the concentration is too low, the trapping and killing effect is poor, the concentration is too high, the solution is too viscous, and the fruit fly bait liquid attractant is not easy to spray for use.

The liquid attractant for the fruit flies has the following beneficial effects:

(1) when combined with water, the formed sprayable attractant gel can be dispensed with, creating a very large attraction for fruit flies.

(2) The resulting mixture gel has the following advantageous characteristics, which are not present in current commercial protein bait concentrates: when stored in a sealed container, it is physically and microbiologically stable; can be thickened into a sprayable gel within 5 to 10 minutes without waiting for more than 24 hours.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to examples, but those skilled in the art will appreciate that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention.

Example 1: comparison of the Properties of different formulations

The formula of yeast powder, soybean meal, skim milk powder, xanthan gum, guar gum, ethanol, propylene glycol and polyethylene glycol as the attractant concentrate is prepared according to the formula proportion in table 1 to form a viscous liquid mixed solution without precipitation, table 1 shows the viscosity of the attractant concentrate prepared according to each proportion of ethanol base, when the propylene glycol or the polyethylene glycol is used as the liquid base, the viscosity of the attractant concentrate is similar to that of the ethanol base, and the description is not listed here. 10g of the liquid mixture was added to 200 ml of water to simulate the concentration of the gel-type bait spray used by farmers in the field. The mixture was stirred for 5 minutes and then allowed to stand for another 5 minutes. This formed a protein bait gel with properties similar to those of a conventional commercial attractant spray.

TABLE 1 attractant concentrate formulations and Properties

Example 2: comparing the luring ability of different formulas to fruit flies

Observations were made using a combination of Bactrocera dorsalis, a mixture of protein and thickener, and 0.2% malathion, an organophosphorous insecticide, to determine which combination was effective, the formulation was as follows: 42 parts of protein, 8 parts of thickening agent and 50 parts of water-soluble alcohol, and when the bait is used, a 0.2% malathion solution is added to ensure that the concentration of the bait in the solution is 10%.

Approximately 100 freshly emerged bactrocera dorsalis (male-female combination) were released from each cage, taking 10 cages. Shoots of 30cm length were selected from peach trees and each shoot was sprayed with 5ml of different types of bait (yeast powder/xanthan gum, yeast powder/guar gum, soy protein/xanthan gum, soy protein/guar gum, milk powder/xanthan gum, milk powder/guar gum) and compared to untreated peach shoots and the mortality observed after 24 hours, see table 2.

TABLE 2 efficiency of trapping and killing Bactrocera dorsalis by various formulations and combinations

Formulation of	Live fly	Dead fly	The trapping and killing rate%
				Yeast powder/xanthan gum	12	86	88％
Yeast powder/guar gum	3	100	97％
				Soybean flour/xanthan gum	15	89	86％
Soybean meal/guar gum	4	91	96％
				Milk powder/xanthan gum	39	73	65％
Milk powder/guar gum	22	74	77％
				Soybean powder	24	77	76％
Yeast powder	29	59	67％
				Milk powder	33	50	60％
Without treatment	90	2	2％

Although soybean powder, yeast powder and milk powder can be used as food sources of the bactrocera dorsalis and can be used as trapping and killing attractants, the soybean powder and the yeast powder are easier to attract the bactrocera dorsalis than the milk powder. Guar gum performs slightly better than xanthan gum as a thickener in this case. The addition of the thickening agent obviously improves the trapping efficiency of the bait.

Example 3: comparing the attraction ability of different liquid-based attractants to Bactrocera dorsalis

Two attractants with better trapping and killing effects and a thickener combination are selected and prepared for testing the influence of different water-soluble alcohols on the trapping effect of the Bactrocera dorsalis Hendel. The attractant comprises soybean meal/yeast powder: guar gum: 42% of water-soluble alcohol (ethanol, polyethylene glycol, propylene glycol): 8%: 50 percent. The attractant was diluted with an aqueous solution containing 0.2% malathion at a concentration of 10% by weight in the aqueous solution of malathion and observed to determine which combination was most effective.

Approximately 100 freshly emerged bactrocera dorsalis (male-female combination) were released from each cage, taking 10 cages. Selecting 30 cm-long twigs on a peach tree, spraying 5ml of different attractants on each twigs, comparing the twigs with the twigs of the peach tree which is not treated, and observing the death rate of the bactrocera dorsalis in 24 hours.

TABLE 3 effectiveness of different liquid-based attractants

Formulation of	Live fly	Dead fly	The trapping and killing rate%
				Soy flour/guar gum/ethanol	4	91	96％
Yeast powder/guar gum/ethanol	3	100	97％
				Soybean meal/guar gum/polyethylene glycol	12	85	88％
Yeast powder/guar gum/polyethylene glycol	10	90	90％
				Soy flour/guar gum/propylene glycol	8	95	92％
Yeast powder/guar gum/propylene glycol	7	94	93％
				Without treatment	90	2	2％

Although the attractants prepared by the three liquid bases used in the test can have good attracting and killing effects on the bactrocera dorsalis, the attracting and killing rate is obviously higher than that of the control, the attractants with the ethanol base have better attracting and killing effects on the bactrocera dorsalis.

Example 4: comparison of attraction effects of diluted attractants with different concentrations on Bactrocera dorsalis

An ethanol-based bactrocera dorsalis attractant formula is selected and prepared for testing the attracting effect of the concentrated attractant on the bactrocera dorsalis. The attractant comprises soybean meal: guar gum: ethanol content is 42%: 8%: 50 percent.

The attractant is diluted to 2%, 5%, 10% and 15% by using an aqueous solution containing 0.2% of malathion, the diluted solution can be easily sprayed, and the attractant diluted by more than 5%, particularly the attractant diluted by 10% and 15% is obviously thicker than water.

Approximately 100 freshly emerged bactrocera dorsalis (male-female combination) were released from each cage, taking 10 cages. Selecting 30 cm-long twigs on a peach tree, spraying 5ml of attractant with different dilution concentrations on each twig, and comparing with the twigs of the peach tree which is not treated, and observing the death rate of the bactrocera dorsalis in 24 hours. The effect of dilution factor 2% is less effective than other dilution concentrations. The attractant can be used within 5 minutes after being diluted.

TABLE 4 effectiveness of different dilution concentrations of attractant

Concentration of dilution	Live fly	Dead fly	The trapping and killing rate%
				2％	29	77	73％
5％	7	94	93％
				10％	3	96	97％
15％	4	98	96％
				Without treatment	88	1	1％

Example 5

Selecting yeast powder/guar gum/ethanol as 42%: 8%: 50 percent of attractant, diluting the attractant by using an aqueous solution containing 0.2 percent of malathion, wherein the weight concentration of the attractant in the aqueous solution of the malathion is 10 percent; preparing yeast powder/water with the ratio of 84%: 16% of attractant, the guar gum/water preparation is 16%: 84% of thickening agent, mixing uniformly, standing for use, observing the time required for the thickening agent to reach a usable state after standing, mixing the attractant and the thickening agent in a weight ratio of 1: 1 after the thickening agent reaches the usable state (the time is about 12 hours), and diluting the mixed attractant by using an aqueous solution containing 0.2% of malathion, wherein the weight concentration of the mixed attractant in the aqueous solution of the malathion is 10%.

The time from when the two attractant formulations were ready for use was observed and recorded.

Approximately 100 freshly emerged bactrocera dorsalis (male-female combination) were released from each cage, taking 10 cages. Selecting 30 cm-long twigs on a peach tree, spraying 5ml of different formula attractants on each twig, comparing the attractants with the twigs of the peach tree which is not treated, and observing the death rate of the bactrocera dorsalis within 24 hours, wherein the table 5 is shown in detail.

TABLE 5 waiting time for different attractants to reach sprayable conditions

Formulation of	Waiting time
		Yeast powder/guar gum/ethanol	After being added with water, the mixture is shaken up and immediately available without waiting
Yeast powder/water	12 hours

Experiments show that the thickening agent needs to be prepared before the aqueous protein attractant is used, the prepared thickening agent needs to wait for more than 12 hours to achieve the thickening effect so as to be convenient for spraying, and the effectiveness of different attractants is specifically shown in table 6.

TABLE 6 effectiveness of different attractants

Formulation of	Live fly	Dead fly	Trapping and killing rate
				Yeast powder/guar gum/ethanol	3	96	97％
Yeast powder/water	6	92	94％
				Control	88	1	1％

As can be seen from the table above, the attractant formula disclosed by the invention and a conventional aqueous attractant formula have better trapping and killing effects on Bactrocera dorsalis, the trapping and killing rate is remarkably higher than that of a control, and the trapping and killing rate of the attractant formula disclosed by the invention is higher.

The foregoing describes the general principles and features of the present invention without limitation to the above-described embodiments, and various changes and modifications may be made without departing from the spirit and scope of the invention, which fall within the scope of the claimed invention.

Claims (5)

1. The liquid attractant for the fruit flies is characterized by comprising the following components in parts by weight: 42 parts of protein, 8 parts of guar gum and 50 parts of ethanol, wherein the protein is selected from one or more of yeast powder, soybean powder and skimmed milk powder.

2. The method for preparing the fruit fly liquid attractant of claim 1, which is characterized by sequentially comprising the following steps:

(1) the protein and the guar gum are mixed evenly,

(2) then adding the mixture into ethanol, and stirring to form the thick liquid attractant for the fruit flies.

3. The use of the fruit fly liquid attractant of claim 1 for attracting and killing fruit flies.

4. The application of the fruit fly liquid attractant in claim 3 in trapping and killing fruit flies is as follows: the liquid attractant is diluted by the aqueous solution of the insecticide, the weight concentration of the liquid attractant in the aqueous solution of the insecticide is 2-15%, and the liquid attractant is used by spraying.

5. The use of the liquid fruit fly attractant of claim 4, wherein the insecticide is malathion.