Feb 21, 2018 - Brown Citrus Aphid (BCA), Toxoptera citricida Kirkaldy ... line-powered diaphragm pump operating at 200 psi and calibrated to deliver 101 gpa.
68
Arthropod Management Tests, Vol. 22
D: CITRUS, NUTS, AND AVOCADOS
ORANGE: Citrus sinensis (L.) Osbeck Valencia', 'Pineapple', 'Midsweet', 'Parson Brown', 'Roble', and 'Hamlin' Brown Citrus Aphid (BCA), Toxoptera citricida Kirkaldy
P. A. Stansly, J. M. Conner, and P. W. Carlin University of Florida/IFAS Southwest Florida Res. and Ed. Center 2686 State Road 29 North Immokalee, Florida 34142-9515 (941) 658-3427
(12D)
INSECTICIDAL CONTROL OF BROWN CITRUS APHID ON SWEET ORANGE, 1997: The trial was conducted in the Budwood Foundation Grove located at Southwest Florida Research and Education Center in Immokalee, Florida, on several varieties of sweet orange planted at 15 X 22 ft. spacing. A RCB design was used with 4 replications and 7 treatments plus two checks (one sprayed with water and one unsprayed). Blocks consisted of nine citrus trees in three rows with three trees per row. Plots were single trees separated from adjacent plots by at least two guard trees. Ten shoots bearing unexpanded flush and heavily infested with BCA were tagged at the onset of the trial. Treatments were sprayed on 17 Jun using a trailer-mounted sprayer equipped with a 13" brass GunJet Spray Gun fitted with a hardened stainless steel #3 orifice disc-type nozzle. The sprayer was supplied by a gasoline-powered diaphragm pump operating at 200 psi and calibrated to deliver 101 gpa. On 16 Jun, the colony size of the aphid was evaluated on all tagged shoots using a 6-point rating scale: 0 = no aphids, 1 = 1-12 aphids, 2 = 12-50 aphids, 3 = 50-150 aphids, 4 = 150-500 aphids, 5 = 500-1,000 aphids, and 6 = > 1,000 aphids. The average rating was 3.5 with no significant differences among replications {P < .51). The same 10 shoots were again evaluated 2, 7, 14, and 21 days after treatment (DAT), and additional 5 new shoots were evaluated for recolonization on 7, 14, and 21 DAT. For this latter evaluation, dead aphids were counted as were live aphids in 2 categories, nymphs plus alates and apterae on youngest 3 leaves of each shoot. All treatments had significantly lower aphid ratings 2 DAT than the water and unsprayed checks which were not significantly different from each other. No live aphids were observed on marked shoots sprayed with Metasystox-R or EXP 80667A at either rate, and there were no significant differences among the remaining treatments except for Agri-Mek plus oil compared with oil alone. Ratings were highest on marked control shoots again 7 DAT and lowest on shoots sprayed with EXP 80667A or Metasystox-R. However, recolonization on shoots sprayed with oil or the two treatments that included oil was not different from the checks, in contrast to the remaining treatments without oil. The number of recolonizing aphids 14 DAT was lower than the checks on shoots treated with Metasystox-R, Nexter without oil and EXP 80667A. There were no significant differences among treatments 21 DAT, possibly because flush had hardened off by then and aphid numbers were low on all shoots. Thus, we were able to observe control for 14 days only with foliar treatments, and Nexter showed a greater effect in the absence of oil.
Treatment/ formulation Metasystox-R 2 SC Nexter 75 WP Nexter 75 WP + Sunoco 9 E EXP 80667A 70WP EXP 80667A 70WP Agri-Mek 0.15 EC + Sunoco 9 E Sunoco 9 E Water Untreated check
Rate lb (AI)/ acre or% 1.0 0.315 0.315 2.0% 0.05 0.075 0.0059 2.0% 2.0%
No. Aphids
Colony size
7 DAT
2 DAT
Dead
Alive
Dead
Alive
Dead
Alive
14 DAT
21 DAT
O.Od 1.3bc
0.0c 0.6bc
0.2a 0.2a
4.3c 7.1 be
O.lab 0.2ab
5.1c 5.3c
0.0a 0.0a
0.6a 0.4a
1.6bc O.Od O.Od
0.7bc 0.1c 0.0c
0.9a 0.5a 0.2a
12.9abc 0.6c 1.1c
0.0b O.lab O.lab
24.5abc 10.6bc 1.0c
0.0a 0.0a 0.0a
2.2a 0.5a 0.0a
1.9b 1.2c 3.3a 3.6a
1.2b 1.0b 2.2a 2.5a
0.3a 0.1a 0.2a 0.4a
19.4ab 18.8ab 24.5a 25.5a
O.lab 0.2ab 0.3a 0.0b
47.2ab 25.9abc 37.9abc 62.6a
0.0a 0.0a 0.0a 0.0a
0.7a 2.1a 1.0a 1.3a
Means within a column followed by the same letter do not significantly differ (P = .05, Duncan's MRT)
ORANGE: Citrus sinensis (L.) Osbeck 'Valencia' Brown Citrus Aphid (BCA); Toxoptera citricida Kirkaldy
P. A. Stansly, J. M. Conner, and P. W. Carlin University of Florida/IFAS Southwest Florida Res. and Ed. Center 2686 State Road 29 North Immokalee, Florida 34142-9515 (941)658-3427
(13D)
INSECTICIDAL CONTROL OF BROWN CITRUS APHID ON SWEET ORANGE, 1997: The trial was conducted in a commercial block of four-year-old 'Valencia' orange rooted to Carrizo citrange planted on a 12 X 24 ft. spacing. A RCB block design was used with 4 replications in separate rows and 5 treatments distributed in single-row plots separated by at least one guard tree. At least 10 new shoots not yet fully expanded and heavily infested with BCA were tagged at the onset of the trial. Foliar treatments were sprayed by hand on 24 Jun using a trailer-mounted sprayer equipped with a 13" brass GunJet Spray Gun fitted with a hardened stainless steel #3 orifice disc-type nozzle. The sprayer was supplied by a gasoline-powered diaphragm pump operating at 200 psi and calibrated to deliver 101 gpa. Tagged colonies were evaluated one day prior to treatment and 2, 7, and 14 DAT using a rating scale of 0 to 6:0 = no aphids, 1 = 1-12 aphids, 2 = 12-50 aphids, 3 = 50-150 aphids, 4 = 150-500 aphids, 5 = 500-1,000 aphids, and 6 = > 1,000 aphids. Average colony size was estimated at 4.6 prior to treatments. In addition, aphids were counted on 5 new pieces of the youngest flush that could be found on each tree on 7, 14, 21 and 28 DAT. All treatments significantly reduced aphid populations on marked shoots 2 DAT compared with the untreated check. The effect was still evident 7 DAT, but there were no aphids on marked flush 14 and 21 DAT. Also, 7 DAT, there were significantly more aphids on untreated shoots than on treated shoots but no differences were observed among sprayed treatments. Flush had hardened by 14 DAT and too few aphids were observed on this or subse-
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