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Arthropod Management Tests 2013, Vol. 38 doi: 10.4182/amt.2013.D14 (D14) ORANGE: Citrus sinensis (L.) Osbeck, ‘Hamlin” ASIAN CITRUS PSYLLID AND CITRUS LEAFMINER CONTROL WITH SYSTEMIC INSECTICIDES APPLIED BY SOIL DRENCH, 2012 Philip A. Stansly University of Florida/ IFAS Southwest Florida Res. and Ed. Center 2686 State Road 29 North Immokalee, FL 34142-9515 Phone: (239) 658-3400 Fax: (239) 658-3469 Email: firstname.lastname@example.org, Barry Kostyk Email: email@example.com Asian citrus psyllid (ACP): Diaphorina citri (Kuwayama) Citrus leafminer (CLM): Phyllocnistis citrella Stainton ACP and CLM are key citrus pests in Florida, damaging new shoots and spreading greening disease (“huanglongbing”) or exacerbating citrus canker, respectively. This trial was conducted at the University of Florida Southwest Research and Education Center in Immokalee, Florida, on 2 year old ‘Hamlin’ orange trees budded to ‘US-802’ pummalo x trifoliate rootstock and spaced 8 ft apart within rows spaced at 18 ft. However, rates per acre were based on an assumed density of 150 trees per acre. Eight treatments were assigned to 8 tree plots in an RCB design with 4 replicates. Weeds, debris and leaf litter were removed from beneath each tree prior to application. An 8 oz suspension of each product was applied either 18 or 19 June to bare soil within 8 inches of the trunk of the tree using an EZ-Dose® sprayer operating at a pressure of 45 PSI. Density of ACP adults was assessed on 6 trees per plot by striking a randomly chosen branch 3 times with a length of PVC pipe, dislodging insects onto a white plastic clipboard to be counted as one tap sample. Preimaginal populations were assessed by removing eight young shoots per plot when available and counting psyllid nymphs and CLM larvae and/or mines under a stereomicroscope. Admire Pro, the 12 oz rate of Belay and the 30.4 oz rate Verimark significantly suppressed psyllid adults on all samples dates. The 15.0 oz rate of Verimark was not different from the untreated check on 2, 16, 31 Jul, 26 Sep and 15 Oct. The 20.25 oz rate of Verimark did not reduce adult psyllids on 2, 16 Jul and 15 Oct and the 6 oz rate of Belay (without Induce) was not different from the check on 5 Nov nor was Belay with Induce different from the check on 15 Oct. However, all products except Belay alone at 6 oz/ac provided significant suppression of adult ACP on 5 Nov, 136 days after treatment (DAT). Admire Pro at 14 oz/ac provided better control than the low rate of Verimark except on 23 July, 7-28 Aug or 7 Nov, whereas the same was true for the high rate of Verimark only on 2 and 9 July. A significant difference between the 6 and 12 oz/ac rates of Belay was only seen on the last (5 Nov) sample date and then only when applied without Induce. All treatments significantly reduced the number of psyllid nymphs observed from 9- Jul through 28 Aug. when compared to the untreated control. However, Admire Pro, 12 oz/ac of Belay and 30.4 oz/ac of Verimark resulted in significantly fewer nymphs then the untreated control on 5 Nov, with no significant differences among these treatments. Significantly fewer nymphs were seen on trees treated with Admire Pro compared to the low (15 oz/ac) rate of Verimark on all but the first (9 Jul) sample date, whereas no such differences were seen on any sample date with the 30.4 oz/ac rate, nor with the 20.25 oz/ac rate on the last 4 sample dates. Again, no rate response with Belay until the last sample date, and then only with the low rate applied alone. All treatments significantly reduced the number of CLM larvae observed when compared to the untreated control from 9 Jul to 8 Aug, but the 6 oz rates of Belay were not significantly different from the untreated on 28 Aug and only the 30.4 oz rate of Verimark was significantly better than the untreated on 6 Nov. Our results indicate generally slower action against ACP with Verimark compared to the neonicontinoids, and comparable activity with Belay and Admire in regard to ACP but not CLM, although with Belay was applied at half or a quarter the AI. 1 Arthropod Management Tests 2013, Vol. 38 doi: 10.4182/amt.2013.D14 Table 1 Adults per tap Treatment Rate/acre or %v/v 24-Jun 2-Jul 9-Jul 16-Jul 23-Jul 31-Jul 7-Aug 13-Aug 28-Aug 11-Sep 26-Sep 15-Oct 5-Nov Untreated 4.17 4.83a 4.79a 1.83a 1.58a 0.71a 0.92a 1.88a 1.92a 2.25a 1.42a 0.92a 1.92a Admire Pro 4.6 SC 14.0 oz 2.08 1.00d 0.25d 0.29c 0.04b 0.08b 0.04b 0.00b 0.04c 0.38cd 0.17d 0.21cd 0.46cd Verimark 1.67 SC 15.0 oz 2.21 3.20abc 2.00bc 1.25ab 0.25b 0.67a 0.33b 0.54b 0.54bc 1.42b 0.88abc 0.63abc 0.29cd Verimark 1.67 SC 20.25 oz 3.50 4.45ab 3.00b 1.54a 0.58b 0.17b 0.21b 0.33b 0.88b 0.75bcd 0.58bcd 0.58abc 0.46cd Verimark 1.67 SC 30.4 oz 2.58 3.04bc 2.50b 0.63bc 0.58b 0.17b 0.17b 0.04b 0.25bc 0.25d 0.17d 0.04d 0.25d Belay 2.13 SC 12.0 oz 1.50 1.91cd 0.63d 0.00c 0.13b 0.08b 0.08b 0.00b 0.00c 0.17d 0.46cd 0.08d 0.88bcd Belay 2.13 SC 6.0 oz 2.58 0.95d 1.04cd 0.38c 0.13b 0.08b 0.13b 0.04b 0.08c 0.54cd 0.38cd 0.33bcd 1.42ab Belay 2.13 SC + Induce 6.0 oz + 0.25% 2.92 0.95d 0.92cd 0.17c 0.13b 0.08b 0.21b 0.33b 0.33bc 1.04bc 1.17ab 0.67ab 1.04bc Means followed by same letter within a column are not statistically different LSD P>0.05) Table 2 Nymphs per flush Rate/acre Treatments or %v/v 9-Jul 16-Jul 23-Jul 8-Aug 28-Aug 6-Nov Untreated 60.40a 45.65a 12.40a 26.79a 36.88a 17.69a Admire Pro 4.6 SC 14.0 oz 1.90bc 0.25d 0.00c 0.00c 0.13d 3.78cd Verimark 1.67 SC 15.0 oz 14.30bc 20.10b 3.60b 9.50b 9.46b 11.09abc Verimark 1.67 SC 20.25 oz 17.40b 16.20bc 3.55b 0.83c 2.00cd 7.50bcd Verimark 1.67 SC 30.4 oz 8.25bc 9.85bcd 0.30c 0.54c 1.13d 1.34d Belay 2.13 SC 12.0 oz 0.20c 0.15d 0.00c 0.33c 0.79d 6.81bcd Belay 2.13 SC 6.0 oz 6.15bc 3.05d 0.55c 2.83bc 5.67bcd 18.16a Belay 2.13 SC + Induce 6.0 oz + 0.25% 2.55bc 5.10cd 0.00c 3.33bc 9.83b 12.68ab Means followed by same letter within a column are not statistically different LSD P>0.05) Table 3 Leafminer larvae per 3 leaves Rate/acre Treatments or %v/v 9-Jul 16-Jul 23-Jul 8-Aug 28-Aug 6-Nov Untreated 1.25a 1.70a 1.45a 2.45a 4.33a 0.50bc Admire Pro 4.6 SC 14.0 oz 0.00b 0.15b 0.00b 0.17cd 1.54bc 0.50bc Verimark 1.67 SC 15.0 oz 0.00b 0.25b 0.05b 0.08d 0.58cd 0.50bc Verimark 1.67 SC 20.25 oz 0.30b 0.05b 0.00b 0.00d 0.08d 0.28bcd Verimark 1.67 SC 30.4 oz 0.00b 0.05b 0.00b 0.08d 0.17d 0.00d Belay 2.13 SC 12.0 oz 0.00b 0.30b 0.05b 1.04b 2.75b 0.72ab Belay 2.13 SC 6.0 oz 0.15b 0.50b 0.35b 0.71bc 4.58a 1.09a Belay 2.13 SC + Induce 6.0oz+0.25% 0.10b 0.20b 0.15b 1.17b 4.42a 0.25cd Means followed by same letter within a column are not statistically different LSD P>0.05)
Arthropod Management Tests – Oxford University Press
Published: Jan 1, 2013
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