Department of Entomology—041
College of Agricultural and Natural Sciences
John T. Trumble
| COLLEGE OF NATURAL AND AGRICULTURAL SCIENCES DEPARTMENT OF ENTOMOLOGY RIVERSIDE, CA 92521 | Phone: (951) 827-5624 Email: john.trumble@ucr.edu Fax: (951) 827-5624 |
California Pepper Commission
Research Report 2011-2012
- IDENTIFICATION
- California Pepper Commission.
- Insect Pest Management on Peppers
- Proposal for period beginning March 2011, ending February 2012.
- Principal Investigator:
Dr. John T. Trumble
Department of Entomology
University of California, Riverside - Cooperating Personnel:
William Carson, Greg Kund and Casey Butler
Department of Entomology
Univ. of California, Riverside - Locations of Work:
U.C. Riverside,
U.C. South Coast Res. & Ext. Center
Ventura and Orange Counties, CA - Insects
- Tomato/Potato Psyllid: Bactericera cockerelli (Sulc)
- Beet armyworm (BAW): Spodoptera exigua (H¸bner)
- Tomato Fruitworm(TFW): Helicoverpa zea (Boddie)
- Leafminer: Liriomyza sativae (Blanchard)
- Leafminer: Liriomyza trifoilii (Burgess)
- Lygus bugs: Miridoa spp.
- Stink bugs (SB): Pentatomidae spp.
- Pepper weevil (PW): Anthonomus eugenii Cano
- Field Screening Trials for Effective Pesticides
Seedlings were transplanted in a sandy loam type soil on 23-24 May at the University of California's South Coast Research and Extension Center. Experimental plots were 3 rows wide (5-ft centers) by 40 ft long and separated by a 3-ft buffer. The pepper transplants were drip irrigated (water pH 7.2 -7.5). Treatments were replicated 4 times in a RCB block design. Application dates and a treatment list are shown in Table 1. All applications were made at twilight. A tractor-mounted boom sprayer with 6 nozzles per row incorporated D-3 orifice disks, #25 cores, and 50 mesh screens. Operating pressure was 125 psi delivering 100 gpa. All treatments included Dyne-amic as an adjuvant at 0.25% vol/vol.
Table 1: Pepper Chemical Trial List of Treatments 2011Treatment #
Compound
Rate-Product
Application Dates
Company
1
Control
-
-
-
2
2A) Admire Pro SC
2B) Movento 240 SC+
Baythroid 2 EC
2C) Oberon 240 SC+
Synapse 240 WG14.0 oz/Ac
5.0 oz/Ac
2.8 oz/Ac
8.5 oz/Ac
3.0 oz/Ac6/1
6/23
7/21, 8/4, 8/25Bayer
3
MBI 206
1 gal/Ac
7/21, 7/28, 8/4, 8/11, 8/25, 8/31
Marrone Biosciences
4
MBI 206
2 gal/Ac
7/21, 7/28, 8/4, 8/11, 8/25, 8/31
Marrone Biosciences
5
MBI 203
1 gal/Ac
7/21, 7/28, 8/4, 8/11, 8/25, 8/31
Marrone Biosciences
6
MBI 203
3 gal/Ac
7/21, 7/28, 8/4, 8/11, 8/25, 8/31
Marrone Biosciences
7
MBI 203 DF
4 lb/Ac
7/21, 7/28, 8/4, 8/11, 8/25, 8/31
Marrone Biosciences
8
Radiant SC
6 oz/Ac
7/21, 8/4, 8/25
Dow
9
Intrepid 2F +
Pounce 3.2 EC10 oz/Ac
8 oz/Ac7/21, 8/4, 8/25
Dow
FMC10
Tolfenpyrad
21 oz/Ac
7/21, 7/28, 8/4, 8/11, 8/25, 8/31
Nichino
11
Low Input
Voliam Flexi 40 WG
Dipel DF
7.0 oz/Ac
1 lb/Ac
7/21, 8/4, 8/11
Syngenta
Valent12
Lannate 2.4 LV
Pounce 3.2 EC+48 oz/Ac
8 oz/Ac6/23, 7/21, 7/28, 8/4, 8/11, 8/25
Dupont
FMC
Harvest
On 6-7 Sep, 200 mature-green to ripe fruit were harvested from the center row of each replicate (800 per treatment) and examined for internal damage by the tomato fruitworm (TFW), external damage by the beet armyworm (BAW), and they typical cosmetic damage caused by stink bugs SB. One hundred fruit were also inspected for damage from pepper weevils (PW).
Results
Figure 1. Potato Psyllid infestation
Potato psyllids were strongly affected by pesticide applications. For the second year, applications of Lannate plus Pounce resulted in significantly higher populations of psyllids. Another treatment including Pounce (#9), also increased psyllid populations. Treatment #11, with Volium Flexi, also caused an increase. At this time it appears that at least Pounce can be assumed to increase populations, and this material should be used with caution.
Figure 2. Pepper weevil damage
Internal damage by PW was high this year with the control sustaining 57% damage (Figure 2). Populations were remarkably high. Damage was lowest in the IPM trial (#2), and in treatments with Marrone Biosciences 206 and in treatments #9 and #10 from Dow and Nichino compounds, respectively. However, none of the materials provided a particularly high level of control.
Figure 3. Calyx feeding damage
Calyx feeding damage (figure 3) was lowest in treatment #8 (Dow's Radient) and the Lannate/Pounce combination (#12). This sets up a conflict between using a Lannate/Pounce combination to reduce calyx damage, and these compounds causing outbreaks of the psyllid populations. At this point, it appears that Radient would be the best choice. Damage to the calyx could be attributed to TFW, BAW, and PW feeding.
Figure 4. Lepidopteran damage
Lepidopteran pressure was moderate (Figure 4). There were no significant differences between any treatments for Lepidopterous insect damage.
Leafminer populations were low, and no statistical separation was possible on any sample dates. The results of dead adult parasites were not included this year due to low numbers. No phytotoxicity was observed in any of the treatments.
- IPM strategies in Peppers
Seedlings were transplanted in a sandy loam type soil on 23-24 May June at the University of California's South Coast Research and Extension Center. Experimental plots were 3 rows wide (5-ft centers) by 40 ft long and separated by a 5-ft buffer. The pepper transplants were drip irrigated (water pH 7.2 -7.5). Treatments were replicated 4 times in a RCB block design. This year the IPM program was incorporated into the chemical screening trial. Treatment 1 was the control and treatment 11 was an IPM rotation. Treatment 12 was a chemical standard. Applications were made as specified in (Table 1). All applications were made at twilight. A tractor-mounted boom sprayer with 6 nozzles per row incorporated D-3 orifice disks, #25 cores, and 50 mesh screens. Operating pressure was 125 psi delivering 100 gpa. All treatments included Dyne-amic as an adjuvant at 0.25% v/v. Leafminer populations and effects on leafminer parasites were evaluated by weekly counts of leafminer pre-pupae and pupae and dead adult parasites in four 9x11 inch trays/replicate from 13 July through 9 September, inclusive. On (23 August), all of the mature-green to ripe fruit were harvested from the center row of each replicate. The number and weight of the fruit were recorded for harvest yield data. From each replicate 100 fruit were sub-sampled (400 per treatment) and examined for Lepidopterous internal damage (tomato fruitworm) and external damage (beet armyworm)(Figure 3). Fruit were also inspected for damage to the calyx, and from pepper weevils (Figure 4), hemipterous pests and presence of psyllids (Figure 1). The results for insect damage are summarized in (Table 2).
Lepidopteran pressure was low. Internal damage from tomato fruitworm was not significant this year. Internal damage by pepper weevil was high this year. There were moderate levels of damage to the calyx and there were differences between the treatments. Leafminer populations were low, and no statistical separation was possible on any sample dates. The results of dead adult parasites were not included this year due to low numbers recorded from the tray counts. No phytotoxicity was observed in any of the treatments. We did see a difference between the chemical standard and IPM rotations for the infestation levels of psyllids. There was a significant increase in psyllid numbers in treatment 9 and chemical standard treatments. These treatments used carbamates and pyrethrins which can kill beneficial insects and actually cause an increase in the numbers of psyllids.
Table 2. Mean Number of Fruit Damaged/Replicate bTreatment
Formulation
Rate Amt/acre
Internal
External
All Leps
Pepper Weevil Internal
Calyx Damage
Bugs
1
Control
-
0.50
15.00
15.50
56.67 c
20.5 bc
1.25
2
2A) Admire Pro SC
2B) Movento 240
SC +Baythroid 2 EC
2C) Oberon 240 SC
+Synapse 240 WG14.0 oz
5.0 oz
2.8 oz
8.5 oz
3.0 oz0.00
15.00
15.00
18.00 a
12.25 ab
1.00
3
MBI 206
1 gal
0.00
14.25
14.25
18.50 a
22.0 c
2.25
4
MBI 206
2 gal
0.00
15.00
15.00
21.25 ab
15.0 abc
0.50
5
MBI 203
1 gal
1.00
14.50
15.50
31.00 ab
15.25 abc
1.25
6
MBI 203
3 gal
0.75
15.00
15.75
40.00 bc
13.75 abc
1.50
7
MBI 203
2 gal
0.50
11.75
12.25
19.25 ab
13.25 abc
1.00
8
Radiant SC
6 oz
0.00
10.25
10.25
25.00 ab
6.50 a
2.00
9
Intrepid 2F +
Pounce 3.2 EC10oz
8 oz0.25
9.25
9.50
15.25 a
13.50 abc
1.00
10
Tolfenpyrad
21 oz
0.75
14.50
15.25
13.50 a
17.25 bc
0.50
11
Low Input
Voliam Flexi 40 WG
Dipel DF
7.0 oz
1 lb0.25
8.00
8.25
22.00 ab
18.50 bc
1.50
12
Lannate 2.4 LV
Pounce 3.2 EC +48 oz
8 oz0.75
8.25
9.00
25.33 ab
8.0 a
0.50
ANOVA F Value
(by column)0.949
0.991
1.046
2.668
2.174
0.581
ANOVA P value
(by column)0.507
0.473
0.429
0.014
0.039
0.832
b Means in columns followed by the same letter are not significantly different (P<0.05 level, Fisher's Protected LSD Test). Internal damage due primarily to (TFW); external damage due primarily to (BAW). Bugs include Lygus and (SB). Calyx damage can be attributed to (TFW), (BAW), and (PW) feeding - Biological Control of the psyllid
Studies were conducted to determine what key beneficial insects were present in Orange and Ventura County pepper fields that could potentially suppress psyllids. Tamarixia triozae was identified as the primary beneficial insect found within the pepper fields and is being considered for commercial production for use in augmentative releases in peppers (Figure 5). This is useful because in potatoes, the Tamarixia triozae accounted for less than 1% of the beneficial insects. As these insects become commercially available, we will test to determine if psyllid populations can be reduced by augmentative releases.
Figure 5. Psyllid natural enemies
- Additional Research
Studies to determine the longevity and mobility of thiamethoxam and imidacloprid in the soil are underway. We are testing alternative strategies and chemicals for psyllid control such as repellents to disrupt insect behaviors. Successful repellents will be incorporated into an IPM program. - Additional Funding Support
Funding from the Pepper Commission has been leveraged by acquiring additional financial support for our pepper research. We have received monetary awards from the SCRI and USDA RAMP funding agencies to study and develop pepper IPM program strategies.