SOIL DRENCH APLICATIONS OF INSECTICIDES FOR CONTROL

Arthropod Management Tests 2014, Vol. 39
doi: 10.4182/amt.2014.D16
(D16)
ORANGE: Citrus sinensis (L.) Osbeck, ‘Hamlin”
SOIL DRENCH APLICATIONS OF INSECTICIDES FOR CONTROL OF ASIAN CITRUS PSYLLID AND
CITRUS LEAFMINER 2013
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: pstansly@ufl.edu,
Barry Kostyk
Email: bkostyk@ufl.edu
Asian citrus psyllid (ACP): Diaphorina citri Kuwayama
Citrus leafminer (CLM): Phyllocnistis citrella Stainton
ACP is a key citrus pest in Florida, attacking young flush and spreading the devastating huanglongbing (HLB) or citrus
greening disease. Mining by CLM exacerbates citrus canker disease. Young trees flush often and therefore require constant
protection afforded by systemic insecticides applied as soil drenches. The objectives of this trial were to compare drenches
of 2 neonicontinoids and one non-neonicotinoid to the standard imidacloprid. Two-year old ‘Hamlin’ orange trees spaced
10 ft apart within rows spaced at 22 ft or 198 trees per acre were used at the University of Florida Southwest Florida
Research and Education Center in Immokalee, Florida. Rates used were based on a density of 180 trees per acre. Seven
treatments were assigned to 5 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 20 May to bare soil within 8
inches of the trunk using an EZ-Dose® sprayer operating at 45 psi. Due to heavy rains preceding the applications irrigation
was not used prior to or after treatment. The adult psyllid population was monitored on 28 May 5, 11, 19, 26 Jun and 3 Jul
the by striking a randomly chosen branch 3 times with a length of PVC pipe on each of the 5 trees in each plot to dislodge
insects onto a white plastic clipboard to be counted as one tap sample. At the same time five shoots were removed from
each plot and examined for ACP nymphs in the laboratory using a stereomicroscope. The numbers of leafminer larvae were
counted on the bottom three leaves of each shoot. Data were analyzed by LSD contingent of a significant F (P = 0.05)
value.
Significant treatment effects on adult psyllids were not seen until 11 Jun, 19 days after treatment (DAT), with a lapse again
on 19 Jun (Table 1). Most reduction was observed with Belay through 3 Jul followed by Venom and Admire Pro which
persisted through 11 and 26 Jun respectively. Significant suppression of adults compared to the check was seen only with
the 20.8 oz rate of Beleaf and only on 26-Jun. Significant treatment effects on nymphs were seen on all sample dates first
with Belay on 28 May then Admire Pro and Venom at 5 Jun. Belay again provided the greatest and most persistent
reduction of nymphs through 3 Jul, significantly greater than Admire Pro and Venom which lost activity at least 2 weeks
earlier. The high rate of Beleaf showed activity on 19 and 26 Jun. Suppression of CLM was seen from all products on 28
May, all but the two lower rates of Beleaf on 5 Jun, but only Admire Pro on 11 Jun (Table 3). A 1.57 inch rainfall
registered at the Immokalee FAWN weather station the afternoon of the application likely leached product from the root
zone and reduced effectiveness of all neonicotinoid treatments in proportion to their solubility in water. This research was
supported by industry gifts of funding and insecticides.
1
Arthropod Management Tests 2014, Vol. 39
doi: 10.4182/amt.2014.D16
Table 1
Adults per tap
Product/
Formulation
Rate
amt/acre
Untreated Check
Admire Pro 4.6 SC 7.0 oz
Belay 2.13 SC
6.0 oz
Venom 70 SG
3.0 oz
Beleaf 50 SG
6.3 oz
Beleaf 50 SG
12.6 oz
Beleaf 50 SG
20.8 oz
28-May 5-Jun 11-Jun 19-Jun
2.50
1.70
0.90
0.80
2.25
1.55
1.40
3.10
2.50
1.80
3.00
4.05
4.50
1.55
3.65a
1.00c
0.70c
1.60bc
2.50ab
2.30b
2.40ab
1.45
1.10
0.50
1.00
1.00
1.35
0.90
26-Jun
3-Jul
1.40a
0.45cd
0.40cd
0.25d
1.05abc
1.20ab
0.50bcd
1.50ab
1.00bc
0.20c
0.70bc
1.20ab
1.90a
0.70bc
Means within columns followed by same or no letter are not statistically different
(LSD, P>0.05).
Table 2
Nymphs per flush
Product/
Formulation
Untreated
Admire Pro 4.6 SC
Belay 2.13 SC
Venom 70 SG
Beleaf 50 SG
Beleaf 50 SG
Beleaf 50 SG
Rate
amt/acre
7.0 oz
6.0 oz
3.0 oz
6.3 oz
12.6 oz
20.8 oz
28-May
5-Jun
11-Jun 19-Jun
50.50abc
71.53a
12.00d
43.76abc
22.33cd
56.53ab
36.13bcd
22.84a 15.88ab 50.15a
4.75b 2.85c
24.40b
3.05b 1.68c
6.11c
5.05b 7.85bc 18.81bc
26.61a 18.80a 53.4a
10.65b 17.05a 28.25b
31.30a 7.80bc 21.13bc
26-Jun
3-Jul
58.50a
40.20ab
9.78c
43.95ab
48.70ab
34.00b
36.25b
40.95a
21.15bc
14.15c
32.44ab
40.21a
33.21ab
27.85abc
Means within columns followed by same letter are not statistically different (LSD, P>0.05).
Table 3
Leafminer Larvae/3 leaves
Product/
Formulation
Rate
amt/acre
28-May
5-Jun
11-Jun
Untreated
Admire Pro 4.6 SC
Belay 2.13 SC
Venom 70 SG
Beleaf 50 SG
Beleaf 50 SG
Beleaf 50 SG
7.0 oz
6.0 oz
3.0 oz
6.3 oz
12.6 oz
20.8 oz
6.29a
0.64d
1.17cd
1.88bcd
3.20bc
3.67b
3.10bc
3.82a
1.80bc
1.15c
2.40bc
3.17ab
2.45abc
1.60c
0.75ab
0.00c
0.25bc
0.45bc
1.07a
0.70ab
0.53abc
Means within columns followed by same letter are not
statistically different (LSD, P>0.05).
2