Developing an Easily Used Bait Monitoring Method for Oriental Fruit Moth in Mating Disruption Orchards PROJECT LEADER: COOPERATORS: Walter Bentley Andrew Molinar RESEARCH SUMMARY Bait Bucket traps track Oriental fruit moth well in both mating and non mating disruption orchards, we were not able to devise a simpler more lasting trap that provides the same level of information as does the Bait Bucket. I believe this can still be accomplished, particularly with the Yellow Bucket Trap container, with some modification of the evaporative surface. My lab will be refining this work without request for funding in 2009. When a more positive trap system is identified I will request funding for more in depth work. I will also be contacting pheromone chemists in the hopes of utilizing their expertise in developing a more useful OFM bait. The work with the Standard Bait Buckets indicates that moth flight information gained in their use can be used for determining biofix in mating disruption orchards. Currently the method for optimum timing is based on degree-day calculation. This method can be found at (http://www.ipm.ucdavis.edu/weather/ddretrieve.html). This is the UC IPM web site for calculating degree-days. The specific timing is 500 to 600 degree days (F) after first moth of the second flight. Without moths being trapped in pheromones this timing is not easily determined. But, with the validation of OFM seasonal flight using Bait Buckets and comparing to OFM trapped in pheromone traps during 2007 and 2008, the optimum timing can be determined. We will be refining Bait Bucket moth catch for determining the need to apply supplemental sprays, but the current level of 50 Oriental fruit moth trapped in the generation prior to harvest seems to be accurate. Oriental fruit moth trap catches greater than 50 moths per week occurred in only 2 orchards and this was after harvest. 41
INTRODUCTION Oriental fruit moth (OFM), Grapholitha molesta Busk, is the key insect pest infesting peaches and nectarines. It is commonly controlled either through insecticides, or mating disruption or both. Approximately 70% of the fresh market peach and nectarine production utilizes OFM mating disruption. The greatest weakness of this approach is migration of moths from outside sources. In such situations, mated moths invade the orchard and their offspring infests fruit. Supplemental sprays can help alleviate this problem, but the timing of those applications is difficult to determine because moths are not caught in pheromone monitoring traps. Over the last three years, a pest management demonstration and implementation project has shown the usefulness of Oriental fruit moth liquid bait for monitoring moths in mating disruption orchards. The recipe for this bait is 5 gallons of water, 4 lbs of brown sugar, 10 mls of terpinyl acetate, and 1 ounce of emulsifier. One to two quarts of this mixture is placed in a bucket hung from a tree and it is changed weekly. Although this method of monitoring is effective, it is cumbersome and time consuming. The following objectives were investigated to make the OFM bait more easily utilized for monitoring. OBJECTIVES 1. To develop a bait trap for Oriental fruit moth that requires less maintenance, is easy to handle, is inexpensive, and monitors both males and female OFM (allows for identifying mated females). 2. To develop treatment thresholds for OFM in mating disruption orchards based on the generation that will occur prior to fruit harvest. 3. If the above objectives are met, to educate farmers and Pest Control Advisors in the usefulness of such traps as guides for supplemental OFM sprays. METHODS AND MATERIALS Trap Comparisons The initial proposal was to test 3 types of dispensers for monitoring. We evaluated an additional 5 traps because 2 of the proposed designs did not trap moths or dispensed too much bait. One of the first designs to be evaluated consisted of a wicking device that contained the liquid bait mixture (approximately 2 ounces) and this was placed within a standard delta sticky traps. This device is called an Air Care Wick and it is currently being used as an air freshener dispenser. It is approximately the size of a human thumb. This dispenser evaporated in 1 night and no moths were trapped. The trap design was dropped from experimentation. 42
The small battery operated pump (Cole-Palmer diaphragm pump that delivers.003 gpm) displaces almost 1 gallon of liquid during the 5 hours of OFM flight each night. This amount is far greater than we could contain for 1 weeks time. The.003 gallon per minute delivery was the smallest amount for these battery operated devices. The yellow covered bucket (see Figure 1) with reduced evaporation area was evaluated in comparative tests with the Standard Bait Bucket. This was the design described as a Better Trap in the initial proposal. The trap used here was manufactured by Trece Inc. The initial testing, in March and April, compared 4 standard bait buckets (64 ounces of bait) and 4 yellow/white Trece Pherocon bucket traps (64 ounces of bait) with the top flat cover removed. This left a small hole for attraction and evaporation. Subsequent tests compared custom designed OFM traps and were performed in a mixed fruit block of Kearney. Figure 2 shows a description of these bucket traps. Reading from left to right: 1 gallon milk container with a Pherocon 2c sticky trap surface fit over opening, traditional 2 quart trap with cone sticky trap forming a funnel over the opening, Traditional 2 quart trap with fitted sticky lid (50, 1/8 inch holes in lid, Alex Trap), Pherocon CRW trap with wick (8 ounces of bait in trap) with cone sticky trap covering, Pherocon VI trap with 8 ounce plastic cup container covered by a 16 mesh screen netting. These were all compared against the Standard 64 ounce open Bait Bucket shown in Figure 3. The concept was to reduce evaporation of bait from traps while attraction to OFM was maintained. If this could be done traps would require less maintenance and frequency of observation. These tests were run during the peak of moth flights. Field Threshold Studies The second objective was performed in 5 orchards where moths were trapped in Standard Bait Buckets. Five gallons of bait were prepared and used to fill buckets. The prepared bait lasts approximately 1 month. A single Bait Bucket is used for orchards 5 acres or less in size. The orchards included two not using mating disruption (Fantasia Nectarine and mixed peach varieties, including O Henry peach, Flavorcrest peach, August Glo nectarine, Mayglo nectarine, Loadel peach, and Ross peach. Three orchards were under mating disruption were also monitored. These included two Spring Bright nectarine orchards and one August Lady peach orchard. Two OFM pheromone traps were also placed in these orchards during the season. The Bait Bucket OFM catches were sexed and mating status determined. Fruit harvest samples of 1000 fruit were examined for infestation with the exception of the mixed fruit. Each orchard was monitored on a weekly basis. Harvest infestation and total moth catch in Bait Buckets was recorded. 43
RESULTS The first field comparison between the Yellow Bait Bucket (smaller evaporative area) and the Standard Bait Bucket resulted in an average of 1.5 moths per trap per night in the Yellow Trap, while the Standard Bucket averaged 8 moths per trap per night. The Yellow trap, although significantly less effective than the Standard Trap, did catch moths consistently and could serve as a monitoring device. The majority of moths in both traps were male. The Standard Bucket averaged 4 males per bucket while the Yellow Trap averaged 1.25 males per trap. The average number of female moths in the Standard Bucket was 3 while the Yellow bucket averaged 0.25 per bucket. The females in the Yellow Bucket were all mated and only 1 unmated female was found in the Standard Bucket. The mixed fruit test orchard was not under mating disruption. Also important was the rate of evaporation. The Yellow Bucket averaged no loss of liquid bait in 3 days and only 1 ounce in 7 days. This loss was significantly (P<0.05, Fisher s Protected LSD) less than that of the Standard Trap where an average of 12 ounces (1/2 the original bait) for 3 days and 14 ounces in 7 days. The second small scale trial utilized the Pherocon CRW (Corn Rootworm) trap (Figure 4), a small clear cone trap that held 12 ounces of bait mixture and fitted with a sticky trap sidings was not successful. The trap was tested in June and caught zero moths compared to the Standard Bucket Trap that caught an average of 11 moths per week. The evaporation of bait was complete in 4 days, making this trap not useable. A third trial in June comparing the Yellow Bait Bucket with Sticky trap (as described above,) Alex s Bait Bucket with Sticky Trap insert (50 holes per insert), Standard Bait Bucket with Sticky Cone, CRW (Corn Rootworm) with Wick and Cone Sticky Trap, and the Standard Bait Bucket. Figure 5 gives the results of the trap catches. The Standard Bait Bucket far out performed the other traps with 11 moths/ trap/week. The CRW trap again evaporated too quickly but did catch one moth. The Yellow Bucket did not evaporate but only trapped one moth. Results of the final trial performed during the fourth OFM flight in August are given in Figure 6. The Standard Bucket again was quite successful, averaging 41.33 trapping moths/trap/week. The Tupperware canister with 24 ounces of liquid bait averaged one moth per trap per week. Alex s Bait Bucket with 24 ounces of liquid bait and sticky trap insert averaged.83 moths/trap/week. The Standard Bait Bucket fitted with a cone sticky trap averaged.17 moths/trap/week. No moths were trapped in the CRW Trap with the cone shaped sticky surface. Results of Field Monitoring Figure 7 gives the seasonal flight activity for OFM in the mixed fruit orchard without mating disruption. A total of 325 moths were trapped and 156 were female (48% female and 52% male). In this Non mating disruption orchard 76.3% of the females were mated, based on total seasonal trap catch. More importantly, the trap catches for each 44
generation in both the pheromone traps and the bait bucket began on the same date of March 18. Harvest infestation was not taken in this orchard. Figure 8 gives the seasonal flight activity for OFM in the Fantasia nectarine orchard. A total of 109 moths were trapped in the Bait Bucket traps and 49 were female (59% female and 41% male). In this Non mating disruption (just 1 year out of mating disruption) resulted in 76.3% mated females, identical to the previous orchard. Fruit damage from OFM was.5% based on 1200 fruit sampled. Both the pheromone and Bait Bucket catches occurred on March 25. Figure 9 gives the seasonal flight activity for OFM in the first Spring Bright orchard using Isomate Twin Tube Disruption at 1 hanger per tree. A greatly reduced number of moths were trapped in this orchard with only 48 total moths trapped all season. In this Mating Disruption Orchard (15 years+) 46% of the moths were female (54% male) and 23% were mated. No damage was recorded at harvest. Figure 10 gives the seasonal flight activity for OFM in the second Spring Bright orchard using the new Trece Cide Trac disrupters placed at one per tree. Fewer moths were trapped in Bait Buckets with a total of 26 for the season. In this Mating disruption orchard 77% were female and 36% were mated. No damage was recorded at harvest. The final orchard where OFM was trapped was an August Lady orchard using the OFM SLR of Suttera Inc. This orchard has been under mating disruption for 6 years. A total 256 moths were trapped in the single Bait Bucket and 54% were female moths (46% males). Sixty-six percent were mated females. Although the number of moths trapped was substantial, no infestation was found at harvest. Figure 11 presents the abundance of moths, on a weekly basis, during the season. In each of the two non mating disruption orchards, where we trapped OFM in pheromone traps, the Bait Buckets trapped first moths on the same day as the pheromones. This is critically important to establish biofix. Also, in these orchards, total Bait Bucket trapping of moths was substantially higher than in pheromone traps. This was also the case in 2007. Pheromone trap counts were substantially lower than Bait Bucket counts in the two non mating disruption orchards. Again, this was true in 2007. Finally, wherever mating disruption was used, mated females were fewer (as a percentage of total females) than in the two orchards where mating disruption was not used. The lowest level of mating (23% and 36% for the season) was found in the orchards under disruption for more than 10 years. Daily checks were also made at one non disrupted location during the spring flight and compared to pheromone trap catches in the same block. The bait bucket tracked the spring flight identically to the pheromone traps. The second flight was also shown in the bait buckets as starting in on May 8. This second flight was not detected in the pheromone traps and there is no good explanation for this. Figure 12 presents this information. 45
SUMMARY Although the Bait Bucket traps still track Oriental fruit moth well in both mating and non mating disruption orchards, we were not able to devise a simpler more lasting trap that provides the same level of information as does the Bait Bucket. I believe this can still be accomplished, particularly with the Yellow Bucket Trap container, with some modification of the evaporative surface. My lab will be refining this work in 2009 without a request for funding. When a more positive trap system is identified I will request funding for more in depth work. I will also be contacting pheromone chemists hoping to utilize their expertise in developing a more useful OFM bait. The work with the Standard Bait Buckets indicates that moth flight information gained in their use can be used for determining biofix in mating disruption orchards. Currently the method for optimum timing is based on degree-day calculation. This method can be found at (http://www.ipm.ucdavis.edu/weather/ddretrieve.html). This is the UC IPM Web Site for calculating degree-days. The specific timing is 500 to 600 degree days (F) after first moth of the second flight. Without moths being trapped in pheromones this timing is not easily determined. But, with the validation of OFM seasonal flight using Bait Buckets and comparing to OFM trapped in pheromone traps during 2007 and 2008, the optimum timing can be determined. We will be refining Bait Bucket moth catch for determining the need to apply supplemental sprays, but the current level of 50 Oriental fruit moth trapped in the generation prior to harvest seems to be accurate. Oriental fruit moth trap catches greater than 50 moths per week occurred in only 2 orchards and this was after harvest. ACKNOWLEDGEMENTS I wish to thank the for supporting this work. Additionally, I am indebted to farmers, Ty Parkinson, Bill Chandler and Marco Rinaldi, and Pest Control Advisers, Wayne Stogbauer and Jim Mose for their help and guidance. 46
Figure 1. Yellow Bucket Trap with Sticky Trap Bottom. 47
Figure 2. Five Oriental fruit moth trap variations from left to right: 1 gallon milk container with a Pherocon 1C sticky trap surface fit over opening, traditional 2 quart trap with cone sticky trap forming a funnel over the opening, traditional 2 quart trap with fitted sticky lid (50, 1/8 inch holes in lid Alex Trap), Phercon CRW trap with wick (8 ounces of bait in trap) with cone sticky trap, Pherocon VI trap with 24 ounce plastic cup container covered by a 16 mesh screen netting. Figure 3. Standard Oriental Fruit moth Bait Bucket. 48
Figure 4. Corn Rootworm Trap (CRW) 49
Figure 5. Oriental fruit moth captured in four types of bait traps, June 2008 12 11 10 8 Mohts/Trap/Week 6 4 2 1 1 0 0 Alex bucket Yellow bucket CRW with Wick Standard Bait Bucket 50
Figure 6. Oriental fruit moth captured in five types of bait traps, August 2008. 45 41.33 40 35 Number of Moths/Trap 30 25 20 15 10 5 0 1 0.83 0.17 0 vmb w/screen alex bucket bb w/ cone rootworm trap w/sticky Bait Bucket 51
Figure 7. Oriental fruit moth flight activity, no disruption, mixed fruit, 2008. 70 Pheromone Total Bait Bucket Male Unmated female Mated female 60 50 OFM/Trap 40 30 20 10 0 2/26 3/11 3/25 4/8 4/22 5/6 5/20 6/3 6/17 7/1 7/15 7/29 8/12 8/26 9/9 9/23 10/7 10/21 52
Figure 8. Oriental fruit moth flight activity, no disruption, Fantasia, 2008. 25 Total BB OFM Male OFM Female Mated Unmated Female Pheromone Trap Ave 20 OFM/Bait Bucket 15 10 2/26 3/4 3/11 3/18 5 3/25 4/1 4/8 4/15 4/22 4/29 5/6 5/13 5/20 5/27 6/3 6/10 6/17 6/24 7/1 7/8 7/15 7/22 7/29 8/5 8/12 8/19 8/26 9/2 9/9 9/16 9/23 9/30 10/7 0 53
Figure 9. Oriental fruit moth flight activity, mating disruption, 1 st Spring Bright, 2008. 9 Total BB OFM Male OFM Female Mated Unmated Female Pheromone Trap Ave 8 7 6 OFM/Trap 5 4 3 2 1 0 3/18 4/1 4/15 4/29 5/13 5/27 6/10 6/24 7/8 7/22 8/5 8/19 9/2 9/16 9/30 54
Figure 10. Oriental fruit moth flight activity, mating disruption, 2 nd Spring Bright, 2008. 5 Total BB OFM Male OFM Female Mated Unmated Female Pheromone Trap Ave 4 3 OFM/Trap 2 1 0 3/18 4/1 4/15 4/29 5/13 5/27 6/10 6/24 7/8 7/22 8/5 8/19 9/2 9/16 55
Figure 11. Oriental fruit moth flight activity, mating disruption, August Lady, 2008. 60 Total BB OFM Male OFM Female Mated Unmated Female Pheromone Trap Ave 50 40 OFM/Trap 30 20 10 0 3/17 3/31 4/14 4/28 5/12 5/26 6/9 6/23 7/7 7/21 8/4 8/18 9/1 9/15 9/29 56
Figure 12. Daily Oriental fruit moth flight activity, no mating disruption, mixed fruit, 2008. 6 Pheromone N Pheromone S BB-C 5 4 3 2 1 0 2/26 3/4 3/11 3/18 3/25 4/1 4/8 4/15 4/22 4/29 5/6 5/13 5/20 5/27 6/3 6/10 57
This page left intentionally blank. 58