Studies of the impact ofEuseius species (Acari: Phytoseiidae) on citrus mites using predator exclusion and predator release experiments

Autor: H. G. Johnson, James A. McMurtry, Joseph G. Morse
Rok vydání: 1992
Předmět:
Zdroj: Experimental & Applied Acarology. 15:233-248
ISSN: 1572-9702
0168-8162
DOI: 10.1007/bf01246565
Popis: To create plots with differential levels ofEuseius, malathion sprays, highly toxic to phytoseiids but of low toxicity to citrus red mite,Panonychus citri (CRM), and citrus thrips,Scirtothrips citri, were applied to blocks of “Valencia” oranges for three seasons (1984, 1985 and 1986) and “Eureka” lemons for one season (1985). Releases ofEuseius spp. were made in plots within the treated blocks. In 1984, CRM populations were highest in the treated/no release plot, lowest in the untreated and intermediate in the treated/Euseius stipulatus-release plot. In 1985, CRM populations were high in all plots in the oranges (including theE. tularensis release) except theE. stipulatus-release plot, and in all plots in the lemons except the untreated.Euseius releases in the lemons had no effect, apparently because they were followed by very hot weather. In 1986, CRM was very low in all plots.Euseius stipulatus became the dominant phytoseiid species even in theE. tularensis-release plots after a few weeks, indicating that this species colonized more readily and spread to other trees more rapidly than didE. tularensis. The results support the hypothesis thatE. stipulatus is an important mortality factor contributing to CRM control at low levels.Euseius stipulatus also may have a negative impact on the citrus rust mite,Phyllocoptruta oleivora. Citrus thrips populations were low during the entire study period and did not differ significantly between plots.
Databáze: OpenAIRE
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