This paper reviews the potential for using insect pathogens to control the Colorado potato beetle,Leptinotarsa decemlineata,and summarizes results from nearly 10 years of research by USDA-ARS-PPRU scientists aimed at ...This paper reviews the potential for using insect pathogens to control the Colorado potato beetle,Leptinotarsa decemlineata,and summarizes results from nearly 10 years of research by USDA-ARS-PPRU scientists aimed at developing methods and strategies for integrated use of Bacillus thuringiensis and Beauveria bassiana for biologically-based management of potato beetles in the northeastern USA.The described studies have resulted in 1)design of a tractor-mounted hydraulic spray system that improved targeting and consequent efficacy of microbial control agents,2)discovery of synergism between the bacterial pathogen Bacillus thuringiensis(Bt)and the fungal pathogen Beauveria bassiana(Bb),3)findings that substantial mortality of beetle larvae treated with B.bassiana during foliar spray programs did not occur until after they entered the soil to pupate,and 4)observations that spray applications made in the evening(at sunset)were significantly,but not substantially,more effective than applications made during the morning hours.These findings have led to development of a bio-based pest management system based on three spray applications made in the following order at 3-5-day intervals:Bt alone,Bt and Bb mixed,and Bb alone.This spray program,with the applications initiated at 50% egg hatch,is intended to control the actively feeding larval stages(providing protection from defoliation)and reduce survivorship to the adult stage(providing long-term control by reducing populations of overwintering adults).In the initial test of the integrated management system,beetle control and potato yields were statistically equivalent to those in plots in which the beetles were controlled with chemical insecticides.Demonstration of the effectiveness of this program will continue over the next 2-3 field seasons.展开更多
In agriculture, chemical insecticides are widely used to protect crops from insect pests. Over a period of years, some insects such as Colorado potato beetle （CPB） succeed in developing resistance to most of the reg...In agriculture, chemical insecticides are widely used to protect crops from insect pests. Over a period of years, some insects such as Colorado potato beetle （CPB） succeed in developing resistance to most of the registered chemical insecticides. Consequently, heavy applications of chemical insecticides to control this pest become ineffective on a long-term basis and can lead to serious health and environmental problems. The use of natural enemies to control CPB is an interesting alternative to chemical means However, hand release of predators is not feasible on a large scale in the field. The main objective of this research study was to design and build a test bench to investigate the technical feasibility of mechanically releasing predators. The test bench consisted of a vertical chain conveyor mounted on two vertical shafts driven by an electric motor. Since the predators are small and fragile, they were placed in a specially designed container to preserve their physical integrity. Trials using this test bench showed that a carrier material was required, because most of the predators remained inside the container. The success of this mass predator release system will be highly valuable for the biological control of insect pests in many crops.展开更多
The CPB （Colorado potato beetle）, Leptinotarsa decemlineata （Say）, is the major insect pest of potato crops in North America, Europe and Asia. Large amounts of chemical insecticides are used to control this insect...The CPB （Colorado potato beetle）, Leptinotarsa decemlineata （Say）, is the major insect pest of potato crops in North America, Europe and Asia. Large amounts of chemical insecticides are used to control this insect pest. Also, the CPB has developed over the years a resistance to most of the registered chemical insecticides, including those that were effective at one time. One of the most promising alternatives to chemical insecticides consists of taking advantage of natural enemies. The use of the stinkbug predator Perillus bioculatus to control the CPB has been successful at small scale. However, this natural enemy is not abundant in the nature and its hand release at large scale is not realistic. To remedy to this problem, predators must be massively released in potato fields using a mechanical distributor. Such a machine has been successfully designed and built at the Department of Soils and Agri-Food Engineering of University Lavak In this distributor, masses of predators are placed in small containers and mixed with a carrier material. In the field, the containers are mechanically opened at different locations, based on a source-point mass release option. These locations are determined in advance following a field monitoring of the populations of CPBs. Field trials proved that the mechanical distributor is reliable and ease of use. Its efficiency in releasing insect predators is high and comparable to that obtained in previous laboratory tests.展开更多
In field and laboratory conditions the reproductive potential （survival at different stages of development） of the Colorado potato beetle has been measured, the dependence of the parameters of insects fertility on v...In field and laboratory conditions the reproductive potential （survival at different stages of development） of the Colorado potato beetle has been measured, the dependence of the parameters of insects fertility on varietal features of the feed has been investigated, the food activity of the representatives of insects from four areas of the Southern Urals has been measured, the intensity and time of hypersensitivity reactions on potato leaves has been defined. In laboratory experiments, the level of activity of hydrolytic enzymes in insects and the level of activity of these enzymes inhibitors in the leaves of three potato varieties differing in their resistance to the Colorado potato beetle have been determined. The results show that the insects-representatives of different samples have different food activity in relation to different potato varieties. High mortality rates were revealed at feeding with leaves of potato of the Bashkir variety characterized by a high level of hydrolases inhibitors and relatively rapid development of necrotic reactions after the appearance of eggs laying on the leaves. We suppose that the neerogenetic barrier appearing in the form of necrosis is the major cause of the fetal mortality of insects. The level of the content of inhibitors inactivating larvae digestive enzymes affects the survival of insects at postembryonic stages. The speed of the necrosis emergence, the level of activity of digestive enzymes inhibitors in potato can be considered as criteria for the selection of breeding material for resistance to the Colorado potato beetle.展开更多
The CPB （Colorado potato beetle） is unquestionably the major insect pest of potato crops in North America, Europe, and Asia. The use of chemical insecticides to control this insect pest started in the 1860s. To date...The CPB （Colorado potato beetle） is unquestionably the major insect pest of potato crops in North America, Europe, and Asia. The use of chemical insecticides to control this insect pest started in the 1860s. To date, no registered chemical has been capable of effectively managing this agricultural pest. Moreover, the CPB has developed over the years a resistance to most of the registered chemical insecticides. The biological control through manual release of natural enemies of the CPB has been successful at small scale. However, hand release of these predators at large scale is not realistic. The objective of this study was to investigate the effectiveness of controlling the CPB through mechanical release of predator insects under real conditions in a potato field. Obtained results indicate that the mechanical release of predator insects resulted in a better control of the CPB populations and egg masses than the manual release. The success of this mechanical release of predator insects in potato fields will be highly valuable for the biological control of insect pests in many other row crops such as strawberry, lettuce, etc..展开更多
文摘This paper reviews the potential for using insect pathogens to control the Colorado potato beetle,Leptinotarsa decemlineata,and summarizes results from nearly 10 years of research by USDA-ARS-PPRU scientists aimed at developing methods and strategies for integrated use of Bacillus thuringiensis and Beauveria bassiana for biologically-based management of potato beetles in the northeastern USA.The described studies have resulted in 1)design of a tractor-mounted hydraulic spray system that improved targeting and consequent efficacy of microbial control agents,2)discovery of synergism between the bacterial pathogen Bacillus thuringiensis(Bt)and the fungal pathogen Beauveria bassiana(Bb),3)findings that substantial mortality of beetle larvae treated with B.bassiana during foliar spray programs did not occur until after they entered the soil to pupate,and 4)observations that spray applications made in the evening(at sunset)were significantly,but not substantially,more effective than applications made during the morning hours.These findings have led to development of a bio-based pest management system based on three spray applications made in the following order at 3-5-day intervals:Bt alone,Bt and Bb mixed,and Bb alone.This spray program,with the applications initiated at 50% egg hatch,is intended to control the actively feeding larval stages(providing protection from defoliation)and reduce survivorship to the adult stage(providing long-term control by reducing populations of overwintering adults).In the initial test of the integrated management system,beetle control and potato yields were statistically equivalent to those in plots in which the beetles were controlled with chemical insecticides.Demonstration of the effectiveness of this program will continue over the next 2-3 field seasons.
文摘In agriculture, chemical insecticides are widely used to protect crops from insect pests. Over a period of years, some insects such as Colorado potato beetle （CPB） succeed in developing resistance to most of the registered chemical insecticides. Consequently, heavy applications of chemical insecticides to control this pest become ineffective on a long-term basis and can lead to serious health and environmental problems. The use of natural enemies to control CPB is an interesting alternative to chemical means However, hand release of predators is not feasible on a large scale in the field. The main objective of this research study was to design and build a test bench to investigate the technical feasibility of mechanically releasing predators. The test bench consisted of a vertical chain conveyor mounted on two vertical shafts driven by an electric motor. Since the predators are small and fragile, they were placed in a specially designed container to preserve their physical integrity. Trials using this test bench showed that a carrier material was required, because most of the predators remained inside the container. The success of this mass predator release system will be highly valuable for the biological control of insect pests in many crops.
文摘The CPB （Colorado potato beetle）, Leptinotarsa decemlineata （Say）, is the major insect pest of potato crops in North America, Europe and Asia. Large amounts of chemical insecticides are used to control this insect pest. Also, the CPB has developed over the years a resistance to most of the registered chemical insecticides, including those that were effective at one time. One of the most promising alternatives to chemical insecticides consists of taking advantage of natural enemies. The use of the stinkbug predator Perillus bioculatus to control the CPB has been successful at small scale. However, this natural enemy is not abundant in the nature and its hand release at large scale is not realistic. To remedy to this problem, predators must be massively released in potato fields using a mechanical distributor. Such a machine has been successfully designed and built at the Department of Soils and Agri-Food Engineering of University Lavak In this distributor, masses of predators are placed in small containers and mixed with a carrier material. In the field, the containers are mechanically opened at different locations, based on a source-point mass release option. These locations are determined in advance following a field monitoring of the populations of CPBs. Field trials proved that the mechanical distributor is reliable and ease of use. Its efficiency in releasing insect predators is high and comparable to that obtained in previous laboratory tests.
文摘In field and laboratory conditions the reproductive potential （survival at different stages of development） of the Colorado potato beetle has been measured, the dependence of the parameters of insects fertility on varietal features of the feed has been investigated, the food activity of the representatives of insects from four areas of the Southern Urals has been measured, the intensity and time of hypersensitivity reactions on potato leaves has been defined. In laboratory experiments, the level of activity of hydrolytic enzymes in insects and the level of activity of these enzymes inhibitors in the leaves of three potato varieties differing in their resistance to the Colorado potato beetle have been determined. The results show that the insects-representatives of different samples have different food activity in relation to different potato varieties. High mortality rates were revealed at feeding with leaves of potato of the Bashkir variety characterized by a high level of hydrolases inhibitors and relatively rapid development of necrotic reactions after the appearance of eggs laying on the leaves. We suppose that the neerogenetic barrier appearing in the form of necrosis is the major cause of the fetal mortality of insects. The level of the content of inhibitors inactivating larvae digestive enzymes affects the survival of insects at postembryonic stages. The speed of the necrosis emergence, the level of activity of digestive enzymes inhibitors in potato can be considered as criteria for the selection of breeding material for resistance to the Colorado potato beetle.
文摘The CPB （Colorado potato beetle） is unquestionably the major insect pest of potato crops in North America, Europe, and Asia. The use of chemical insecticides to control this insect pest started in the 1860s. To date, no registered chemical has been capable of effectively managing this agricultural pest. Moreover, the CPB has developed over the years a resistance to most of the registered chemical insecticides. The biological control through manual release of natural enemies of the CPB has been successful at small scale. However, hand release of these predators at large scale is not realistic. The objective of this study was to investigate the effectiveness of controlling the CPB through mechanical release of predator insects under real conditions in a potato field. Obtained results indicate that the mechanical release of predator insects resulted in a better control of the CPB populations and egg masses than the manual release. The success of this mechanical release of predator insects in potato fields will be highly valuable for the biological control of insect pests in many other row crops such as strawberry, lettuce, etc..
