Comparison of standard (granular, drench) and novel
(tablet, stick soak, root dip) imidacloprid treatments for cottonwood leaf
beetle 
Imidacloprid is used on agricultural and ornamental crops against a wide
variety of pests, but data on efficacy and duration for various treatments
are needed. Standard drench studies demonstrated protection for 524 months
against hemlock wooly adelgid, Adelges tsugae (Annand), on hemlock (Cowles
et al. 2006, Steward and Horner 1994, Webb et al. 2003).
Our studies showed that a novel imidacloprid stick soak killed Chrysomela
scripta for 10 months after treatment on greenhousegrown poplar (Tenczar &
Krischik 2006). A novel tablet study protected eucalyptus for 1.7 years (Collett
& McBeath 2007) and root dip studies protected rose for 2.5 months against
Japanese beetle, Popillia japonica Newman, (Gupta & Krischik 2007) and peach
for 3 months against black peach aphid, Brachycaudis persicae, (Passerini)
(Shearer & Frecon 2002).
Our objectives were to determine the efficacy and duration of imidacloprid
for field and containergrown hybrid poplar.
Hypothesis
Efficacy and duration for all standard and novel treatments in the field and
greenhouse will be 12 months.
Methods

NM6 polar sticks were planted on 14 June 2004 in both the field and in
containers in three blocks.

Imidacloprid treatments (granular, drench, and tablets) were applied on 30
July 2004 (greenhouse containers) and 6 August 2004 (field).

Granular treatments were applied at 0.12x0.5x to match amount of active
ingredient (AI) with other treatments.

Stick soak treatments were hydrated for 48 hours in solution prior to
planting.

Root dip treatments were hydrated for 5 minutes in solution prior to
planting.

Beetle survivorship was evaluated
for 12 months after 96hour exposure to leaves from imidaclopridtreated
and untreated plants.
Results: Field Poplars

Granular (0.5x) and tablet (0.25x and 0.5x) treatments killed adults for
12 mo.

Granular (0.12x, 0.25x, and 0.5x), drench (0.5x and 1x), and tablet (0.25x
and 0.5x) treatments killed larvae for 12 mo.

Drench (0.25x) and stick soak (0.5x, 1x, and 2x) treatments killed larvae
for 1 mo.
Results: Greenhouse Containerized Poplars

Granular (0.12x, 0.25x, and 0.5x), drench (0.5x, 1x, and 2x), tablet
(0.25x, 0.5x, and 1x), and stick soak (2x) treatments killed adults and
larvae for 12 mo.

Stick soak (0.5x, 1x, and 2x) and root dip (1x, 2x, and 4x) treatments
killed adults for 8 mo and larvae for 12 mo.

Field Poplars 
Adults % Survivorship 
Larvae % Survivorship 
Treatment 
Rate 
1 mo 
12 mo 
1 mo 
10 mo 
12 mo 
Control 
N.A. 
91.7 a 
99.1 a 
90.0 a 
100.0 a 
91.2 a 
Granular 0.12x 
0.125 g (AI) 
38.3 cde 
100.0 a 
3.3 ef 
33.3 bc 
55.6 bcd 
Granular 0.25x 
0.25 g (AI) 
8.3 de 
94.9 a 
0.0 f 
16.7 bc 
41.7 cd 
Granular 0.5x 
0.5 g (AI) 
6.7 e 
67.1 c 
0.0 f 
0.0 c 
0.0 e 
Drench 0.25x 
0.12 g (AI) 
83.3 a 
98.1 a 
30.8 cd 
50.0 abc 
73.6 ab 
Drench 0.5x 
0.24 g (AI) 
40.0 bcd 
95.4 a 
0.8 f 
25.0 bc 
36.1 d 
Drench 1x 
0.48 g (AI) 
10.0 de 
92.1 ab 
3.3 ef 
0.0 c 
24.1 de 
Tablet 0.12x 
0.125 g 
43.3 bc 
97.2 a 
15.0 def 
16.7 bc 
68.5 abc 
Tablet 0.25x 
0.25 g 
23.3 cde 
71.8 c 
20.8 cdef 
0.0 c 
2.8 e 
Tablet 0.5x 
0.5 g 
71.7 ab 
79.4 bc 
54.2 b 
0.0 c 
2.8 e 
Stick Soak 0.5x 
0.24 g (AI)/L 
88.3 a 
100.0 a 
55.0 b 
100.0 a 
76.5 ab 
Stick Soak 1x 
0.48 g (AI)/L 
93.3 a 
99.0 a 
42.5 bc 
75.0 ab 
70.3 abc 
Stick Soak 2x 
0.96 g (AI)/L 
81.7 a 
99.0 a 
22.8 cde 
75.0 ab 
70.1 abc 
Root Dip 0.5x 
0.24 g (AI)/L 
Root dip treatments in the field died or were stunted;
therefore these treatments were excluded from the field study. 
Root Dip 1x 
0.48 g (AI)/L 
Root Dip 2x 
0.96g (AI)/L 
F (df),
P ANOVA 
49.1 (12, 70), <0.001 
13.3 (12, 217), <0.001 
17.6 (12, 182), <0.001 
10.1 (12, 65), <0.001 
21.8 (12, 216), <0.001 

Greenhouse Poplars 
Adults % Survivorship 
Larvae % Survivorship 
Treatment 
Rate 
1 mo 
8 mo 
12 mo 
1 mo 
8 mo 
12 mo 
Control 
N.A. 
98.6 a 
100.0 a 
95.8 a 
88.8 a 
76.2 a 
86.4 a 
Granular 0.12x 
0.125 g (AI) 
5.6 c 
0.0 b 
4.2 c 
0.0 c 
0.0 b 
0.0 c 
Granular 0.25x 
0.25 g (AI) 
8.3 c 
0.0 b 
4.2 c 
0.0 c 
0.0 b 
0.0 c 
Granular 0.5x 
0.5 g (AI) 
2.8 c 
0.0 b 
0.0 c 
0.0 c 
0.0 b 
0.0 c 
Drench 0.5x 
0.24 g 
2.8 c 
8.3 b 
0.0 c 
0.0 c 
0.0 b 
0.0 c 
Drench 1x 
0.48 g 
9.7 c 
0.0 b 
0.0 c 
0.0 c 
0.0 b 
0.0 c 
Drench 2x 
0.96 g 
4.2 c 
0.0 b 
0.0 c 
0.0 c 
0.0 b 
0.0 c 
Tablet 0.25x 
0.25 g 
47.2 b 
0.0 b 
4.2 c 
27.9 b 
0.0 b 
0.0 c 
Tablet 0.5x 
0.5 g 
38.9 b 
0.0 b 
4.5 c 
13.9 bc 
0.0 b 
0.0 c 
Tablet 1x 
1.0 g 
33.3 b 
0.0 b 
4.5 c 
13.9 bc 
0.0 b 
0.0 c 
Stick Soak 0.5x 
0.24 g (AI)/L 
1.4 c 
25.0 b 
66.7 ab 
0.0 c 
0.0 b 
20.8 bc 
Stick Soak 1x 
0.48 g (AI)/L 
5.6 c 
8.3 b 
75.0 ab 
0.7 c 
0.0 b 
20.8 bc 
Stick Soak 2x 
0.96 g (AI)/L 
6.9 c 
25 b 
50.0 b 
0.0 c 
0.0 b 
8.3 c 
Root Dip 1x 
0.48 g (AI)/L 
8.3 c 
8.3 b 
81.8 ab 
0.0 c 
0.0 b 
39.4 b 
Root Dip 2x 
0.96 g (AI)/L 
11.7 c 
8.3 b 
64.3 ab 
0.0 c 
0.0 b 
7.1 bc 
Root Dip 4x 
1.9 g (AI)/L 
0.0 c 
8.3 b 
65.0 ab 
0.0 c 
0.0 b 
5.0 c 
F (df),
P ANOVA 
44.5 (15, 269), <0.001 
10.7 (15, 80), <0.001 
28.7 (15, 166), <0.001 
49.8 (15, 269), <0.001 
62.6 (15, 81), <0.001 
15.3 (15, 165), <0.001 

Conclusions
Tablets were as effective or more effective than standard granular and
drench treatments, can protect trees for 1 yr,
and can be reapplied to manage Chrysomela scripta and conserve
biological control agents. Stick soak reduces the amount of (AI) used, but
should be studied at higher rates in the field. Tablets and dormant root
dips can be used in other commodities, such as Christmas trees, nursery, and
landscape.
References
Collett, N. G., and J. McBeath. 2007. Managing
insect pests in Eucalyptus globulus (Labill.) plantations in Victoria
using insecticide tablets at establishment. Aust. For. 70: 5360.
Gupta, G., and V. A. Krischik. 2007. Professional and consumer
insecticides for management of adult Japanese beetle on hybrid tea rose. J.
Econ. Entomol. 100: 830837.
Shearer, P. W., and J. L. Frecon. 2002. Managing Brachycaudis
persicae (Homoptera: Aphididae) during peach orchard establishment. J.
Econ. Entomol. 95: 368371.
Tenczar, E. G., and V. A. Krischik. 2006. Management of cottonwood leaf
beetle (Coleoptera: Chrysomelidae) with a novel transplant soak and
biorational insecticides to conserve coccinellid beetles. J. Econ. Entomol.
99: 102108.
Published here:
Tenczar, E. G., and V. A. Krischik.
2007. Comparison of standard (granular and drench) and novel
(tablet, stick soak, and root dip) imidacloprid treatments for
cottonwood leaf beetle (Coleoptera: Chrysomelidae) management on
hybrid poplar. J. Econ. Entomol. 100: 16111621. 