Dreves, Amy J.

Gadino, Angela N.

Walton, Vaughn M.

Undetermined

KEYWORDS: Typhlodromus pyri, Mites, Fungicides, Vineyard

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 48 Section V Pests of Wine Grapes and Small Fruit Pests  EFFECTS OF SIX VINEYARD FUNGICIDES ON THE  JUVENILE PREDATORY MITE TYPHLODROMUS PYRI  Angela Gadino, Vaughn Walton and Amy Dreves Oregon State University, Department of Horticulture 4127 Ag and Life Sciences Corvallis, OR 97331 gadinoa@hort.oregonstate.edu   Fungicide programs in western Oregon vineyards are believed to contribute to secondary pest outbreaks of the rust mite Calepitrimerus vitis (Nalepa).  Laboratory bioassays were conducted to assess the effects of six vineyard fungicides on Typhlodromus pyri Scheuten (Acari:Phytoseiidae), a key predator mite of C. vitis.  Fungicides tested were micronized sulfur (92%), whey powder (milk bi-product), manganese ethylenebisdithiocarbamate (75%, mancozeb), boscalid (plus pyraclostrobin, 38%), myclobutanil (40%) and paraffinic oil (97.1%) at three different rates (recommended label rate, 1.0X increase and 2.0X increase), a water spray and check (no spray) were also included. Fungicide dilutions were directly sprayed onto juvenile (0-3d) T. pyri with a Potter Precision Spray Tower.  The effects of each treatment were assessed at specified days after treatment (DAT) in order to assess direct mortality, fecundity and oviposition per female.  Results indicate that five of the six fungicides tested can be classified as non-toxic to juvenile T. pyri as levels of mortality were less than 50% for all rates at 7 DAT.  Paraffinic oil was the single fungicide which showed direct mortality greater than 50% at 1 DAT for all three rates, and were significantly different from the check.  Sub-lethal effects were more pronounced among the fungicides tested. Significant decreases were seen in the sulfur (1.0x rate) and mancozeb (1.0x, 2.0x rate) treatments compared to the check.  The percent fecundity reduction relative to the check was highest in the sulfur (28%, 51.2%), myclobutanil (24.7%, 45.7%) and mancozeb (21.8%, 83.2%, 70%) treatments at label rate, 1.0x rate and 2.0x rate, respectively.  Whey powder and boscalid showed no significant differences, at all three rates, from the check and a low percent reduction in fecundity relative to the check. Fecundity comparisons across fungicides of similar rates, did show treatment differences at the 1.0x rate (P ≤ 0.001) and 2.0x rate (P ≤ 0.05).  These results can be utilized as guidelines in vineyard IPM practices to enhance predator mite populations for biological control.              49 Mean % mortality (± SEM)   DAT Treatment Sulfur Check  Rate (g/l) 5.40 7.20 9.50  3  24.0 ± 5.0a 26.7 ± 5.6a 30.7 ± 6.7a 13.3 ± 3.1a          Whey  Check   12.0 18.0 24.0  3  21.3 ± 7.7a 28.0 ± 4.9a 16.0 ± 5.4a 15.1 ± 4.5a          Boscalid  Check   0.94 1.42 1.89  3  26.7 ± 6.9a 9.3 ± 3.4b 22.7 ± 4.9a 8.0 ± 3.3b          Myclobutanil  Check   0.30 0.45 0.60  3  12.0 ± 4.4a 18.6 ± 3.9a 20.0 ± 2.1a 20.0 ± 4.7a          Manzate  Check   2.40 3.60 4.80  3  29.3 ± 11.6a 37.3 ± 10.4a 32.0 ± 16.5a 12.0 ± 3.1a          Paraffinic oil*  Check   15.0 22.5 30.0  3  89.3 ± 5.4a 94.7 ± 5.3a 100 ± 0a 9.3 ± 4.9b      Juvenile mite fecundity reduction in fungicide treatments0102030405060708090LR 1.0X 2.0XRate of treatment% reduction relative to checkSulfurWheyBoscalidMyclobutanilMancozeb        

Effects of Six Vineyard Fungicides on the Juvenile Predatory Mite Typhlodromus Pyri

https://ir.library.oregonstate.edu/downloads/np193c14h

Effects of Six Vineyard Fungicides on the Juvenile Predatory Mite Typhlodromus Pyri

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