Compound bactericide for pear tree pollination period and application thereof

Abstract

The invention discloses a compound bactericide for a pear tree pollination period and application thereof, and belongs to the technical field of fruit tree planting and pesticide application. According to the method, 35% propiconazole and carbendazim compound suspoemulsion (7% propiconazole and 28% carbendazim) serves as a core agent, after being diluted by 2200 times, the suspoemulsion is sprayed in the full-bloom stage of the pear trees in the mode of avoiding the bee collection peak period, and bee colony protection measures are matched. By optimizing the concentration and spraying time of the compound bactericide and matching management, the stress effect of the bactericide on Italian bees is remarkably reduced on the basis of ensuring that the calyx abscission rate of pear fruits is increased (male pears are changed into female pears) and the fruit quality is improved, the death rate of the bees within 24 hours is reduced, and the survival rate of the bees is increased. The enrichment amount of the compound bactericide in bee bodies and bee pollen is controlled, and the bee pollination efficiency is not influenced. The method gives consideration to production benefits and ecological safety of pear trees, and is simple to operate, high in practicability and suitable for application of the compound bactericide in the flowering phase of a large-scale pear tree plantation.

Description

Technical Field

[0001] This invention relates to the field of fruit tree planting and pesticide application technology, and in particular to a compound fungicide for pear trees during the pollination period and its application. Background Technology

[0002] Pear trees are a major economic fruit tree, and their typical self-incompatibility makes them reliant on insects such as bees for pollination to achieve fertilization and fruit set. Bee pollination is widely used in pear production as a cost-effective and efficiency-enhancing method. To improve the calyx-drop rate and fruit quality, pear farmers usually spray compound fungicides (such as 35% propiconazole·carbendazim compound suspension emulsion) during the pear tree flowering period. However, existing spraying methods have significant drawbacks: 1. Improper spraying dosage and timing led to direct exposure of bees to high concentrations of fungicide, resulting in a significant increase in bee colony mortality within 24 hours; 2. The fungicide accumulates in large quantities in the bee's body and bee pollen, with the residual peak appearing 24-72 hours after spraying, which long-term stresses the bee's physiological functions and foraging behavior; 3. Traditional spraying does not take into account the foraging behavior of bees, which leads to a decline in the learning and memory abilities of bees, an imbalance of gut microbiota and metabolic disorders, thereby affecting the efficiency of pollination for pear trees; 4. The lack of supporting measures for bee colony protection and residue monitoring makes it impossible to balance the benefits of improving fruit quality and ecological security.

[0003] Therefore, there is an urgent need to develop a compound fungicide spraying method that takes into account both the needs of pear tree production and bee protection, so as to resolve the contradiction between fungicide application and bee pollination in the existing technology. Summary of the Invention

[0004] The purpose of this invention is to provide a compound fungicide for pear tree pollination and its application, in order to solve the problems existing in the prior art. While ensuring the calyx removal rate and quality of pear fruit, this invention reduces the acute toxicity and long-term stress of the compound fungicide on bees, reduces bee mortality, controls pesticide residues, and ensures pollination efficiency and ecological safety.

[0005] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of this invention is a method for improving the calyx removal rate of pear fruits by spraying a compound fungicide during the pollination period of pear trees, comprising the following steps: (1) The compound bactericide is diluted to obtain a spray solution; (2) Place the beehive in the pear orchard and remove the honey source stored in the honeycomb; (3) Spray the pear trees evenly with the spray solution. The time to spray the spray solution is: before 9:00 am or after 6:00 pm during the peak flowering period when there is no wind or rain.

[0006] Based on the above technical solution, the present invention has the following technical effects: 1. This invention balances fruit quality and bee colony safety: While ensuring the improvement of pear fruit calyx defoliation rate, the mortality rate of bees within 24 hours is reduced by more than 60% compared with traditional methods, and it does not affect the learning ability of bees, only significantly weakening the inhibitory effect on memory ability 6 hours after learning. 2. The pesticide residues of this invention are controllable: the residues of propiconazole and carbendazim in bees and bee pollen are reduced by 30%-50% compared with traditional spraying methods, and the residue peaks decay earlier, reducing the risk of bioaccumulation. 3. Relief of physiological stress in bees: This method can maintain the dynamic balance of the activities of protective enzymes and detoxification enzymes in bees, avoid imbalance of intestinal microorganisms (such as Lactobacillus and Bartonella), and reduce the abnormal expression of 168 differential metabolites. 4. This invention is simple to operate and low in cost: it can be achieved by optimizing concentration, timing and supporting measures without the need for additional equipment investment, and is suitable for large-scale pear orchards. Attached Figure Description

[0007] Figure 1 This is a comparison chart showing the number of dead bees at the hive entrance at different times after spraying.

[0008] Figure 2 The curves show the changes in the residual amounts of propiconazole and carbendazim in bees after spraying.

[0009] Figure 3 The curves show the changes in the residual amounts of propiconazole and carbendazim in bee pollen after spraying.

[0010] Figure 4 The effect of compound fungicide treatment on the calyx defoliation rate of pear fruit. Detailed Implementation

[0011] Unless otherwise specified, the technical solutions described in this invention are all conventional solutions in the field, and the reagents or raw materials used are all purchased from commercial channels or are publicly available unless otherwise specified.

[0012] This invention provides a method for improving the calyx removal rate of pear fruits by spraying a compound fungicide during the pollination period of pear trees, comprising the following steps: (1) The compound bactericide is diluted to obtain a spray solution; (2) Place the beehive in the pear orchard and remove the honey source stored in the honeycomb; (3) Spray the pear trees evenly with the spray solution. The time to spray the spray solution is: before 9:00 am or after 6:00 pm during the peak flowering period when there is no wind or rain.

[0013] In some specific implementation schemes, the compound fungicide is a 35% propiconazole·carbendazim compound suspension emulsion, purchased from Zhaoyuan Sanlian Chemical Co., Ltd.

[0014] In some specific implementations, the dilution factor is 2000-2500 times.

[0015] In some specific implementation schemes, the beehives are placed in the pear orchard 24-48 hours before spraying.

[0016] In some specific implementation schemes, the amount of spraying liquid is controlled so that the flower surface is moistened without dripping.

[0017] The selected compound fungicide and its ratio were based on a 35% propiconazole·carbendazim compound suspension emulsion as the core agent, with propiconazole accounting for 7% and carbendazim accounting for 28%. This ratio ensures effective calyx removal from the fruit while meeting low toxicity standards (acute oral toxicity half-lethal concentration 15.169 μg ai / bee, hazard quotient 49.42).

[0018] The dilution concentration was optimized by diluting the compound fungicide with water 2200 times to obtain the spray solution. This concentration is the optimal value for the recommended field dosage, which can meet the requirements for fungicide and calyx removal while reducing toxic stress on bees and avoiding the disruption of the activity of bees' protective enzymes (superoxide dismutase SOD, catalase CAT, peroxidase POD) and detoxification enzymes (carboxylesterase CarE, glutathione transferase GSTs, cytochrome P450).

[0019] The best time to spray is during the initial flowering stage of pear trees, specifically before 9:00 AM or after 6:00 PM on a windless and rainless day, avoiding the active foraging period of bees (9:00 AM - 6:00 PM) to reduce the probability of bees coming into direct contact with the pesticide.

[0020] The standard spraying method is to use a pesticide spraying vehicle to spray evenly. The amount of spray should be enough to moisten the surface of the flowers without dripping pesticide, so as to avoid excessive pesticide residue on the surface of the flower organs. The spraying area should cover the pear tree flowers and branches to ensure that the calyx removal effect is uniform.

[0021] Bee colony protection measures: (1) 24 hours before spraying, move the bee colonies into the pear orchard and place 3 Italian honeybee colonies with the same colony strength (7 frames) in each orchard. Remove the honey combs in the bee colonies before moving them in. (2) Monitor the number of dead bees at the hive entrance daily for 24-72 hours after spraying and remove dead individuals in a timely manner; (3) Test the pesticide residue in bees and bee pollen at 3, 6, 24, 48, 72, 240 and 360 hours after spraying to ensure that it meets safety standards; (4) The bee colony should not be moved within 360 hours after spraying to avoid the spread of residual pesticides with the bee colony.

[0022] This invention uses a 35% propiconazole-carbendazim compound suspension emulsion (7% propiconazole + 28% carbendazim) as the core agent. After a 2200-fold dilution, it is sprayed during the initial flowering stage of pear trees, avoiding peak bee activity times, and is accompanied by bee colony protection measures. By optimizing the concentration of the compound fungicide, the timing of spraying, and supporting management, this invention significantly reduces the stress effect of fungicides on Italian honeybees, lowers the 24-hour mortality rate of honeybees, controls the accumulation of pesticides in honeybees and bee pollen, and does not affect bee pollination efficiency, while ensuring improved calyx removal rate of pear fruit (achieving the transformation of male pears into female pears) and improved fruit quality. This method balances the production benefits of pear trees with ecological safety, is simple to operate, highly practical, and suitable for fungicide application during the flowering period in large-scale pear orchards.

[0023] The 35% propiconazole-carbendazim compound suspension emulsion used in this invention was purchased from Zhaoyuan Sanlian Chemical Co., Ltd.

[0024] Example 1 I. Experimental Materials and Environment 1. Experimental site: Modern Agricultural Demonstration Park, Yanhu District, Yuncheng City, Shanxi Province (35°10′8″N, 110°55′26″E), two isolated pear orchards of 18 mu each were selected, with a distance of more than 3km between them; 2. Experimental pear trees: The variety is Dangshan crisp pear, the trees are 5 years old, the spacing between trees is 3m×4m, and the growth conditions are uniform; 3. Compound fungicide: 35% propiconazole·carbendazim compound suspension emulsion was purchased from Zhaoyuan Sanlian Chemical Co., Ltd.; 4. Test bee colony: 6 hives of Italian honeybees, 7 frames per hive, excellent queen bee, free from mites and diseases, and uniform colony strength; 5. Experimental instruments: pesticide spraying truck, liquid nitrogen tank, high performance liquid chromatography-tandem mass spectrometry, gas chromatography-tandem mass spectrometry, etc.

[0025] II. Spraying Method Implementation Steps 1. Dilution of the agent: Take 500g of 35% propiconazole·carbendazim compound suspension emulsion, add 2200 catties of water, stir well to obtain the spray solution; 2. Bee colony pretreatment: 24 hours before spraying (19:00 on March 26), place 6 hives into two pear orchards, 3 hives in each orchard, and remove the honey source stored in the honeycomb; 3. Spraying operation: On the morning of March 28th, from 8:00 to 9:00 (windless, rainless, and sunny), the diluted compound fungicide was evenly sprayed on the pear trees in Park 1 using a pesticide spraying truck, while Park 2 was sprayed with water as a control; the amount of spraying was controlled so that the surface of the flowers was moist but not dripping. 4. Subsequent Management: (1) At 12:00, 15:00, 18:00 after spraying and at 12:00 on the following 2-4 days, count the number of dead bees at the hive entrance; (2) Bee samples were collected 1 day before spraying and 3, 6, 24, 48, 72, 240 and 360 hours after spraying. Bee pollen samples were collected 1 day before spraying and 24, 48, 72, 240 and 360 hours after spraying. The residue levels of propiconazole and carbendazim were tested. (3) The bee colony should not be moved within 360 hours after spraying, and dead bees should be cleaned at the hive entrance every day.

[0026] III. Test Results 1. Bee mortality rate: The average number of bees that died in Park 1 within 24 hours was 6.33±1.53, which was 96.9% lower than the traditional spraying method (the traditional spraying method is to spray during the day, and spray in both the morning and afternoon, with a high spraying frequency, and an average mortality rate of 201.4±2.21 bees). The number of deaths dropped to 0 after 4 days. 2. Pesticide residues: 24-72 hours after spraying, the peak residue of propiconazole in bees was 7200 μg / kg, and the peak residue of carbendazim was 45 μg / kg; the peak residue of propiconazole in bee pollen was 230 μg / kg, and the peak residue of carbendazim was 35 μg / kg, all of which met the residue control standards set by this invention. 3. Fruit quality: The rate of calyx removal of pears in Park 1 increased by 38% compared with Park 2, the proportion of "female" pears increased by 42%, and the fullness of the fruit appearance was significantly improved. 4. Bee physiological indicators: The learning ability of bees in Park 1 did not decline significantly. The inhibition rate of memory ability 6 hours after learning was reduced by 50% compared with the traditional method. The relative abundance of Lactobacillus in the gut microbiota decreased by 30%.

[0027] The core of this invention lies in resolving the contradiction between fungicide spraying during pear tree flowering and bee pollination in existing technologies by optimizing the dilution concentration and spraying timing of compound fungicides, and by implementing bee colony protection and residue monitoring measures. The 35% propiconazole-carbendazim compound suspension emulsion used in the examples is a commercially available product. A dilution ratio of 2200 times is the optimal value for the recommended field dosage. This concentration ensures effective calyx removal, improves fruit quality, and controls the acute toxicity of the fungicide to bees at a low-risk level (hazard quotient 49.42).

[0028] Applying the pesticide during periods when bees are less active reduces the probability of direct contact with the pesticide. Accompanying bee colony pretreatment and residue monitoring measures allow for timely monitoring of bee health and pesticide accumulation, preventing large-scale colony losses. Experimental results show that this method balances pear tree production benefits with ecological safety and can be widely applied in large-scale pear orchards nationwide.

[0029] If the application scenario needs to be adjusted, the dilution ratio and spraying timing can be finely adjusted within the range of 2000-2500 times, depending on the local pear tree variety, climate conditions and bee colony type.

[0030] 5. Effect of compound fungicide treatment on the calyx defoliation rate of pear fruit Table 1

[0031] As shown in Table 1 and Figure 4 As shown, the calyx dehiscence rate of the treatment group was significantly higher than that of the traditional spraying control group, which is of great significance for improving the internal and external quality of the fruit and increasing economic benefits.

[0032] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for improving the calyx removal rate of pear fruits by spraying a compound fungicide during the pollination period of pear trees, characterized in that, Includes the following steps: (1) The compound bactericide is diluted to obtain a spray solution; (2) Place the beehive in the pear orchard and remove the honey source stored in the honeycomb; (3) Spray the pear trees evenly with the spray solution. The time to spray the spray solution is: before 9:00 am or after 6:00 pm during the peak flowering period when there is no wind or rain.

2. The method according to claim 1, characterized in that, The compound fungicide is a 35% propiconazole·carbendazim compound suspension emulsion, purchased from Zhaoyuan Sanlian Chemical Co., Ltd.

3. The method according to claim 1, characterized in that, The dilution factor is 2000-2500 times.

4. The method according to claim 1, characterized in that, The beehives should be placed in the pear orchard 24-48 hours before spraying.

5. The method according to claim 1, characterized in that, The amount of spray solution used is controlled so that the flower surface is moistened without dripping.

Images