The Influence of Spray Programs on the Fauna of Apple Orchards in Nova Scotia: Xx. Trends After Altering Levels of Phytophagous Mites or Predators

Abstract

Utilizing the knowledge of their direct effects, the materials ryania, carbaryl, and Animert V-101 applied to a uniformly distributed population of the European red mite, Panonychus ulmi (Koch), altered the populations in plots in an apple orchard. Trends after treatment in both host mite and predator populations were assessed. Supplementary applications of the acaricides Animert V-101 or dicofol directed against certain generations of P. ulmi controlled outbreaks and altered the faunal levels during the following season. Ryania was largely innocuous to most species of predators with the exception of Atractotomus mali (Meyer) and Diaphnocoris spp., carbaryl was detrimental to most predacious species, and Animert V-101, while selectively toxic to phytophagous mites, was innocuous to all predacious insects and Typhlodromus pyri Scheuten.Phytophagous mite populations may be altered to almost prescribed levels with pesticides when the predator populations are known. This allows selective chemicals to be used to complement the predator effect and maintain red mites below the threshold of damage.

DEVELOPMENTAL, SURVIVAL, AND REPRODUCTIVE PARAMETERS OF BERTHA ARMYWORM, MAMESTRA CONFIGURATA (LEPIDOPTERA: NOCTUIDAE) ON FOUR PLANT SPECIES

“…Mites reached a peak density of 57.31leaf just before the animert application (Table 2). Animert was found to be innocuous to the predators but toxic to P. ulmi (Sanford and Herbert 1970). Animert was found to be innocuous to the predators but toxic to P. ulmi (Sanford and Herbert 1970).…”

“…Mite densities peaked at 58.9 mitestleaf in July in the ryania plots whereas the peak in the control plots was 23.7lleaf (Table 2). Carbaryl was found to be harmful to most species of predators (Sanford and Herbert 1970) so there were more mitedayslleaf accumulating in the carbaryl plots until animert was applied to those plots on 7 July. Mites reached a peak density of 57.31leaf just before the animert application (Table 2).…”

“…In this study we examined current-and second-year effects of P. ulmi on fruit production, bloom, and fruit set of Red Delicious apples from the same trees on which Sanford and Herbert (1970) examined relationships between P. ulmi and its predators and Herbert and Butler (1973) estimated the effect of mite-days on foliar levels of nitrogen, potassium, and phosphorous.…”

EFFECT OF POPULATIONS OF THE EUROPEAN RED MITE,PANONYCHUS ULMI, ON THE APPLE VARIETY RED DELICIOUS IN NOVA SCOTIA

“…Dates of application of animert corresponded to the peak numbers of first (animert plots), second (carbaryl plots), and third (ryania plots) generations of P. ulmi (Herbert 1970). Details of supplementary spray programs to control insects and apple scab are given by Sanford and Herbert ( 1970).…”

“…The pesticide treatments applied in 1967 had highly significant (P<0.01) effects on mite-dayslleaf in each year from 1967 to 1970 (Table 1). Sanford and Herbert (1970) attributed differences among the treatments to the direct effects of pesticides on P. ulmi as well as to their impact on predators of P. ulmi that included mirids, anthocorids, thrips, spiders, and the phytoseiid mite, Typhlodromus pyri (Scheuten), that first appeared in the orchard in 1968. They found that ryania was innocuous to later-hatching predators but reduced numbers of the early-hatching Atractotomus mali (Meyer) and Diaphnocoris spp.…”