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The use of benzoylphenyl ureas as novel insecticides for the control of locusts and grasshoppers

The use of benzoylphenyl ureas as novel insecticides for the control of locusts and grasshoppers
The use of benzoylphenyl ureas as novel insecticides for the control of locusts and grasshoppers

Three benzoylphenyl ureas (BPU's); diflubenzuron, hexaflumuron and teflubenzuron were assessed in the laboratory against second (II) instar Desert Locust nymphs, Schistocerca gregaria (Forskål) (Orthoptera:Acrididae). Following treatment of two-day-old II instars by ingestion of a single dose, acute responses revealed that the three compounds gave significantly different LD50s (P<0.05); 67.97, 26.61 and 0.71μg/nymph respectively. The timing of exposure during the II instar four-day inter-moult period and the duration of exposure were found to result in significantly differing acute responses for each compound. The closer to the moult an application was made, the greater the mortality. Increasing the number of exposures for a given quantity of active ingredient also resulted in significantly higher rates of mortality for each BPU. BPU's were found in many cases to significantly prolong the development times of nymphs between II & III and II & IV instars.

Field experiments were carried out using diflubenzuron, barrier-sprayed by ultra-low volume (ULV) techniques onto vegetation, against marching nymphal bands of the Moroccan locust, Dociostaurus marocannus (Thunberg) (Orthoptera: Acrididae) and the Madagascan migratory locust, Locusta migratoria capito (Saussure) (Orthoptera: Acrididae). Individual D. macroccanus bands were exposed to barriers 50m wide and treated at rates ranging from 50 to 75g a.i./ha. All bands were effectively controlled within 15 days and the peak losses of nymphs from each band were correlated with peak moulting within individual bands. Bands also showed reduced displacement when compared with a control band. A larger plot of 4 x 5km was sprayed with 8 barriers (50m wide) at 600m intervals over an area infested with L.m. capito bands at a mass application rate of 93.7g a.i./ha within barriers, equivalent to an overall application rate of 7.8g a.i./ha. The L.m. capito bands were completely controlled within 15 days of spraying. Marching was significantly reduced in treated bands of L.m. capito in comparison with bands from an untreated plot and resulted in many treated bands halting within the barriers which led to their complete control.

University of Southampton
Coppen, George Donald Aylmer
Coppen, George Donald Aylmer

Coppen, George Donald Aylmer (1994) The use of benzoylphenyl ureas as novel insecticides for the control of locusts and grasshoppers. University of Southampton, Doctoral Thesis.

Record type: Thesis (Doctoral)

Abstract

Three benzoylphenyl ureas (BPU's); diflubenzuron, hexaflumuron and teflubenzuron were assessed in the laboratory against second (II) instar Desert Locust nymphs, Schistocerca gregaria (Forskål) (Orthoptera:Acrididae). Following treatment of two-day-old II instars by ingestion of a single dose, acute responses revealed that the three compounds gave significantly different LD50s (P<0.05); 67.97, 26.61 and 0.71μg/nymph respectively. The timing of exposure during the II instar four-day inter-moult period and the duration of exposure were found to result in significantly differing acute responses for each compound. The closer to the moult an application was made, the greater the mortality. Increasing the number of exposures for a given quantity of active ingredient also resulted in significantly higher rates of mortality for each BPU. BPU's were found in many cases to significantly prolong the development times of nymphs between II & III and II & IV instars.

Field experiments were carried out using diflubenzuron, barrier-sprayed by ultra-low volume (ULV) techniques onto vegetation, against marching nymphal bands of the Moroccan locust, Dociostaurus marocannus (Thunberg) (Orthoptera: Acrididae) and the Madagascan migratory locust, Locusta migratoria capito (Saussure) (Orthoptera: Acrididae). Individual D. macroccanus bands were exposed to barriers 50m wide and treated at rates ranging from 50 to 75g a.i./ha. All bands were effectively controlled within 15 days and the peak losses of nymphs from each band were correlated with peak moulting within individual bands. Bands also showed reduced displacement when compared with a control band. A larger plot of 4 x 5km was sprayed with 8 barriers (50m wide) at 600m intervals over an area infested with L.m. capito bands at a mass application rate of 93.7g a.i./ha within barriers, equivalent to an overall application rate of 7.8g a.i./ha. The L.m. capito bands were completely controlled within 15 days of spraying. Marching was significantly reduced in treated bands of L.m. capito in comparison with bands from an untreated plot and resulted in many treated bands halting within the barriers which led to their complete control.

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Published date: 1994

Identifiers

Local EPrints ID: 458624
URI: http://eprints.soton.ac.uk/id/eprint/458624
PURE UUID: 7505a70c-d0eb-4e51-9efb-237bb3c057ea

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Date deposited: 04 Jul 2022 16:52
Last modified: 04 Jul 2022 16:52

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Contributors

Author: George Donald Aylmer Coppen

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