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Effects of Copper on Citrus Rust Mite Populations, 2000
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P. A. Stansly, J. Conner, and D. Peach
University of Florida/IFAS
Southwest Florida Research and Education Center
ORANGE: Citrus sinensis (L.) Osbeck ‘Pineapple'
Citrus rust mite (CRM): Phyllocoptruta oleivora (Ashmead)
Citrus rust mite (CRM) continues to be the major arthropod pest of citrus in Florida. Copper is part of most spray programs for disease control but it has been suspected that copper sprays may flare CRM populations. The objective of this trial was to examine the impact of multiple copper sprays on the CRM population. The trial was conducted at the Duda Grove in Henry county, Florida, on 28-year old ‘Pineapple’ orange trees planted at 17.5 X 21.4 ft. spacing. A RCB design was used to assign 4 treatments including an untreated check to 10 tree plots with a 10 tree buffer between each plot in 2 single rows with 2 replications each separated by a buffer row. A pre-count made 30 Jun on 3 trees per replication produced an average of 2.3 CRM per standard
10x lens field. Treatments were applied on 30 Jun using a Durand Wayland 3P100-32 air blast speed sprayer with an array of seven # 3 T-Jet stainless steel cone nozzles per side, at a pressure of 400 psi which delivered 100 gpa. Treatments were evaluated for CRM incidence 7 times over a 114 day period starting 7 Jul. Four fruit, 2 per side, were sampled from 8 trees for a total of 32 fruit per plot. All mobile CRM were counted in two, 1.5-cm diameter fields using a 10x Bauch and Lomb® Triplex lens on each partially shaded side of each fruit.
Florida Agricultural Experiment Station Journal Series No. N-02001.
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Treatment/
formulation |
Rate
lbs/acre |
Mean number of CRM per lens field (1.5 cm diameter) |
|
7
DATa |
20
DAT |
35
DAT |
49
DAT |
63
DAT |
83
DAT |
114
DAT |
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GX-306 |
4.0 |
4.07a |
2.58a |
2.67a |
7.04ab |
4.97a |
6.83a |
19.16a |
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GX-435 |
6.0 |
5.78a |
4.60a |
2.73a |
10.51a |
4.70a |
5.22a |
9.08b |
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Untreated |
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2.98a |
4.75a |
1.87a |
6.40b |
2.73b |
4.72a |
14.34ab |
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Means in columns followed by the same letter(s) are not significantly different (LSD, P < 0.05)
a Days after treatment
Treatments applied 30 Jun and 14 Aug, DAT 1 and 45 respectively
All treatments over sprayed with 3 lb Kocide 2000 and 5 gal/A oil 28 Aug, 59 DAT
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