Biological control ofOligonychus perseae(Acari: Tetranychidae) on avocado: III. Evaluating the efficacy of varying release rates and release frequency ofNeoseiulus californicus(Acari: Phytoseiidae)

Abstract

Three different release rates and timings of the phytoseiid Neoseiulus californicus (McGregor) were evaluated for Oligonychus perseae Tuttle, Baker, and Abbatiello control on avocado trees in a commercial orchard in southern California, USA. Densities of natural enemies and O. perseae were monitored on trees for 34 weeks that were treated with either one, two, or three releases of 500, 1000, or 2000 N. californicus, or two applications of 5% narrow range (NR) 415 petroleum oil. Predator releases were made when 50% (release one), 75% (release two), or 95% (release three) of sampled leaves were infested with one or more motile O. perseae. Densities of O. perseae on trees treated with N. californicus or petroleum oil were compared to control trees that received no treatments for O. perseae suppression. Release of a minimum of 2000 N. californicus per tree was necessary to significantly reduce O. perseae densities in comparison to control trees. Releasing 1000 N. californicus twice or 2000 N. caIifornicus once provided O. perseae control similar to petroleum oil treatments and to trees treated with cumulative releases totaling more than 2000 predators per tree. This result indicated that releases totaling more than 2000 N. californicus per tree did not substantially improve O. perseae control and the cumulative number of predators released per tree is more important than the number of times N. californicus is released for controlling O. perseae.

Plant-Related Factors Influence the Effectiveness of <I>Neoseiulus fallacis</I> (Acari: Phytoseiidae), a Biological Control Agent of Spider Mites on Landscape Ornamental Plants

“…However, studies have reported that the phytoseiids were effective in suppressing Panonychus ulmi in apples (Monetti & Fernandez 1995), and Tetranychus urticae in citrus (GraftonCardwell et al 1997;Abad-Moyano et al 2010 (Strong & Croft 1995, 1996, ivy geranium (Opit et al 2004), greenhouse vegetable crops (McMurtry 1991;Arthurs et al 2009), and ornamental plants (Hamlen & Lindquist 1981;Pratt & Croft 1998). Many of the above studies demonstrated that release rate/frequency and initial prey density are critical factors that may impact successful biological control of phytophagous mites by the phytoseiids (Hamlen & Lindquist 1981;Hoddle et al 2000;Pratt & Croft 2000;Opit et al 2004;Fraulo & Liburd 2007). For instance, Fraulo & Liburd (2007) reported that release rate and frequency had a great impact on the ability of N. californicus to provide effective and season-long suppression of spider mites on strawberry.…”

Baseline susceptibility of persea mite (Acari: Tetranychidae) to abamectin and milbemectin in avocado groves in Southern California

“…Considerable research has focused on control of California persea mite populations using augmentative releases of various predaceous mite species but released mites do not appear to persist from year-to-year and the cost of effective annual augmentative releases is generally considered to be prohibitive (Kerguelen and Hoddle 1999;Faber et al 2000;Hoddle et al 2000;TakanoLee andHoddle 2001, 2002). These results prompted industry research on the efficacy of narrow-range oil sprays for persea mite control and such treatments were shown to be effective if high concentrations of oil (10%) were used.…”

Gut-content analysis of predatory phytoseiid mites using fluorescent-labeled polymerase chain reaction: age of spider-mite eggs influences detection rates

“…Several phytoseiid mite species (Acari: Phytoseiidae) are candidates for natural enemies of spider mites. Studies have attempted to identify the most effective phytoseiid predators and increase their populations for spider-mite control (e.g., AbadMoyano et al, 2009;Funayama et al, 2015;Hoddle et al, 2000;Katayama et al, 2006;Kishimoto, 2002;Oliveira et al, 2007;Toyoshima, 2003). However, with reduced acaricide use, many phytoseiid species are present in the field, and their small size causes difficulties in determining true spider-mite predators through field observations.…”