THE INFLUENCE OF SPRAY PROGRAMS ON THE FAUNA OF APPLE ORCHARDS IN NOVA SCOTIA: XX. TRENDS AFTER ALTERING LEVELS OF PHYTOPHAGOUS MITES OR PREDATORS

1970 ◽  
Vol 102 (5) ◽  
pp. 592-601 ◽  
Author(s):  
K. H. Sanford ◽  
H. J. Herbert

AbstractUtilizing 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.

1961 ◽  
Vol 93 (10) ◽  
pp. 924-927 ◽  
Author(s):  
F. T. Lord ◽  
D. K. R. Stewart

Prior to 1950 the European red mite, Panonychus ulmi Koch, was a major pest in Nova Scotia apple orchards, and brown mite, Bryobia arborea M. and A., was practically non-existent. Lord (1949), showed that the sulphur fungicides, commonly in use up to that time, were detrimental to some of the predacious species and toxic to the brown mite. After 1950 red mite populations became negligible and, although the brown mites increased, they did not become sufficiently abundant to cause economic damage. This shift of population balance in Nova kotia orchards has been attributed to the gradual replacement of sulphur and other detrimental materials by pesticides less harmful to predators of the mites (Pickett 1953).


1973 ◽  
Vol 105 (12) ◽  
pp. 1519-1523 ◽  
Author(s):  
H. J. Herbert ◽  
K. P. Butler

AbstractA study was conducted in a mature apple orchard in Nova Scotia to compare the density of eggs of the European red mite, Panonychus ulmi (Koch), over the whole tree to their density on a selected area using a random selection and standard selection technique. Both methods provided nearly equivalent estimates of population densities for generations 2 and 4 but not for generation 3. The population estimates based on sampling from the selected area overestimated the whole tree population.Optimum allocation of sampling resources may be obtained by sampling a small number of clusters from each of a large number of trees.


1961 ◽  
Vol 93 (5) ◽  
pp. 380-384 ◽  
Author(s):  
H. J. Herbert

The predacious mites of the subfamily Phytoseiinae are common predators of the phytophagous mites in apple orchards in Nova Scotia. There is little information in the literature on the value of these predators in the control of phytophagous mites or on the food necessary for their development and reproduction. Ballard (1953) found that at 78°F. at least two males of Tetranychus bimaculatus Har. were required daily by Typhlodroms fallacis (Garm.) to complete the protonymphal or the deutonymphal instar. The males and mated females consumed daily an average of 3.9 and 7.5 males respectively from the larva1 to the adult stage. Chant (1960) found that T. pyri required 25 larvae of Panonychus ulmi (Koch), during 26 days to complete development at 64°F. in the absence of plant material or free water. These authors did not study the effects of different amounts of food on the development of these two species of phytoseiids.


1975 ◽  
Vol 107 (8) ◽  
pp. 825-828 ◽  
Author(s):  
H. J. Herbert ◽  
K. P. Butler

AbstractThe number of male and female first generation Panonychus ulmi (Koch) were recorded from 13 apple orchards representing widely different levels of mite infestation on four different varieties. The average percentage of males was 27.5. Statistically significant differences were found among orchards, varieties, observers, and their interactions. No relationship between sex ratio and population density was evident.


1966 ◽  
Vol 98 (9) ◽  
pp. 991-999 ◽  
Author(s):  
K. H. Sanford ◽  
H. J. Herbert

AbstractIn the apple orchards of Nova Scotia DDT, azinphos-methyl or lead arsenate control the winter moth, Operophtera brumata (L.). DDT, even at a low dosage, is detrimental to predators but not to the phytophagous mites Bryobia arborea M. & A. and Panonychus ulmi (Koch); azinphos-methyl is toxic to B. arborea but not to P. ulmi; lead arsenate is of low toxicity to both the phytophagous mites and predators but effective in control of the winter moth when applied against the maturing larvae.


1969 ◽  
Vol 101 (1) ◽  
pp. 62-67 ◽  
Author(s):  
H. J. Herbert ◽  
K. H. Sanford

AbstractMaintenance of predacious arthropods in apple orchards requires both the judicious use of chemical sprays and the presence of adequate food supplies. When the common food source, the European red mite, Panonychus ulmi (Koch), is depleted by either a selective chemical, such as Animert V-101, or by excessive activity of the predators, the apple rust mite, Vasates schlechtendali (Nal.), if present, provides an alternate food. This enables survival of sufficient numbers of predators to prevent resurgence of the red mite within the same season.


1967 ◽  
Vol 99 (7) ◽  
pp. 689-696 ◽  
Author(s):  
K. H. Sanford ◽  
H. J. Herbert

AbstractOvex, tetradifon, and chlorbenside which are largely innocuous, and parathion which is more harmful, to beneficial insects and predaceous mites, have been used in apple orchards in Nova Scotia to control outbreaks of phytophagous mites. Dicofol is used at present but it is toxic to predaceous mites. Animert V-101 is effective against Panonychus ulmi (Koch) but is ineffective on most beneficial species. Dicofol and Animert V-101 initially reduced a high population of P. ulmi but were equally ineffective on predaceous insects. The latter chemical was innocuous to Typhlodromus pyri Scheuten and Vasates schlechtendali (Nal.) but gave partial control of P. ulmi. A similar high population of P. ulmi was reduced to a low level on a comparative untreated plot where a high number of predators was present. This reduction was evident 1 month later than on the treated plots. The overwintering numbers of P. ulmi in 1966 were below a commercially tolerable level on the three plots.


1962 ◽  
Vol 94 (11) ◽  
pp. 1222-1227 ◽  
Author(s):  
R. S. Downing

In British Columbia the control of phytophagous mites, especially the European red mite, Panonychus ulmi (Koch), and the McDaniel spider mite, Tetranychus mcdanieli McG., is becoming increasingly difficult, mainly because of the mites' ability to develop resistance to most acaricides in a relatively short time (3). Because of this, methods of control other than strictly chemical are examined at every opportunity.


1960 ◽  
Vol 40 (1) ◽  
pp. 198-201 ◽  
Author(s):  
Wm. L. Putman ◽  
D. C. Herne

Numbers of the European red mite (Panonychus ulmi Koch) increased but those of the brown mite (Bryobia arborea Morgan & Anderson) and the peach silver mite (Vasates cornutus Banks) decreased after sprays of Sevin (N-methyl-1-naphthyl carbamate) were applied to peach trees. Sevin practically eliminated the predacious mite Typhlodromus rhenanus Oudms., and larvae and pupae of Stethorus punctillum Weise, and greatly reduced the numbers of adults of S. punctillum, chrysopid larvae, and spiders.


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