A novel device for dispensing pheromones into the air of agricultural fields, for the purpose of communication disruption and elimination of mating of pest moth species, is the puffer. These machines release repeated puffs of pheromone from pressurized aerosol cans, with individual puffs often containing pheromone equivalent to millions of female moths. They have a number of advantages, in comparison to traditional hand-applied pheromone-release devices. Because the pheromone is protected from light and oxygen until the moment of release, chemical breakdown is minimized. Two or more pheromones can be mixed and emitted together, giving the opportunity to obtain simultaneous control of more than one species. The amount of pheromone is the same for last puff as it is for the first puff released from the can, giving a predictable amount of pheromone delivered per unit of time. Labor costs for installing puffers are apt to be considerably lower than they are for hand-applied devices. Nine large-acreage, season-long trials were conducted during 1996, 1997 and 1998 to evaluate the puffer technique for management of lepidopterous pests on peaches and table grapes. Four trials on peaches were directed at simultaneous mating disruption and control of the oriental fruitmoth, omnivouous leafroller and the peach twigborer. Five trials on table grapes were directed at mating disruption of the omnivouous leafroller and raisin moth. In these trials, puffers showed high potential for controlling multiple pest species on a wide area, farm-wide basis.
1. Establish laboratory colonies for each Lepidoptera species to be tested.
2. Determine for each species the critical concentration of pheromone components needed to effectively disrupt premating communication of the following major lepidopterous pests of California stone fruit and grapes: Oriental fruitmoth (OFM), peach twigborer (PTB), omnivouous leafroller (OLR), raisin moth (RM), oblique-banded leafroller (OBLR) and orange tortrix (OT).
3. Perform quantitative analysis of various pheromone components, both alone and in mixtures to determine chemical stabilities in the absence of air, and volatility’s when exposed to air.
4. Determine for each species the degree to which their specific pheromone components, presented separately or in mixtures, either enhance or interfere with the efficacy of communication disruption of other species when they are simultaneously exposed to marginally disruptive levels of their own pheromone components.
5. Demonstrate that appropriate combinations of the pheromone components representing each of the lepidopterous pests present in specified 160-acre blocks of grapes or stone fruit can be released together into the air from widely separated mechanical dispensers spaced on ¼-mile grids, providing effective communication disruption of each of the species.
6. Determine and demonstrate the efficacy of this ranch-wide communication disruption system, when it is maintained in 160-acre blocks through the entire effective pest season, by comparing reductions in larval infestations attacking the crop foliage, fruit and stems with reductions that are caused in comparison blocks by presently available commercial pheromone-disruption systems of by presently recommended pesticidal control methods.
7. Measure the edge effect of larval infestation of the respective pests that is caused by female moths that mate in nearby untreated areas and then fly into and lay eggs in the pheromone-protected area.
8. Arrange field days at the 160-acre treated ranches and publish results in newsletters and appropriate agricultural publications to inform interested growers, farm advisors, PCA’s, and regulatory personnel at both state and federal levels with regard to the new technology.
All work sites have been in commercial peach orchards and vineyards the San Joaquin Valley, California.
1. Each of the Lepidoptera species is now reared in our laboratory on a bean-based artificial medium, except RM, which is reared on a bran-based medium. For each species, the sexes are separated while pupae, and virgin female moths are maintained in cages until they are used as bait in monitoring traps for determining the efficacy of synthetic pheromone treatments in interfering with orientation of male moths to females.
2. Our work to date has been directed toward determining optimum pheromone blends and quantities that are needed in order to disrupt premating pheromone communication of OLR, OFM and PTB in peaches and OLR, OT and RM in table grapes. Early research phases were conducted in field plots with miniature pheromone evaporators. These were arrayed in 6 x 6-evaporator grids and separations between evaporators were varied to determine which combinations of these chemicals were best at preventing male moths from locating virgin females and synthetic lure bated traps. OLR consisted of 4 chemical components, of which the two major components only, in a 90:10 blend are needed for communication disruption. This year we found a 75:25 blend was as efficient as the 90:10. The optimum blend of the two component PTB blend is 80:20. OFM is commercially available and consists of three components in a predetermined ratio. RM consists of 1 component. About 50 grams of OLR or OFM pheromones per season provides excellent disruption of communication from mid-March through late October for these species, whereas more PTB, OBLR and RM pheromones are needed for these species. Until the 1998 season the only dispensing cabinet available were indoor restroom deodorizing cabinets sold by Technical Consepts Inc. We now have a puffer cabinet designed for outdoor use that is chemical resistant, water proof and programmable to operate at a times when pheromones are needed. Paramount Farming Company who has registration for or has applied for registration for most pheromones being researched is marketing this cabinet in 1999. In separate tests, we have evaluated the Sentry (formerly Ecogen) “coil” formulated for OLR, OT, PTB, OFM and RM pheromones when applied in vineyards and orchards at the rate of 130 and 260 coils per acre. Each application provided a total of 6.5 or 13 grams pheromone for the season. The OLR and OT provided effective communication disruption for these species for 120 days. OFM provided disruption for 60 days and PTB and RM both disrupted communication for 30 days at best.
3. All of the pheromone materials are singly or doubly unsaturated 10 to 14 carbon chains with acetate, alcohol aldehyde functional groups attached. PTB pheromone is built on 10 carbon, OFM pheromone is built on 12 carbon and RM, OLR, OT and OBLR pheromones are built on 14 carbon chains. Volatility’s of these materials are in a 1:3:10 ratio for 14 to 12 to 10-carbon chain materials respectively. These materials maintain their chemical identity for indefinitely long periods when they are excluded from air, within pressurized aerosol cans.
4. A large amount of cross disruption of communication is encountered among the three leafroller species, OLR, OT and OBLR reflecting certain pheromone components that are identical in the pheromone blends of each of these species. This cross disruption of leafroller species stimulates our continued investigation into a possible generic pheromone blend for all leafroller species. No evidence for a lessening of communication disruption in any target species through simultaneous exposure to the pheromones has been detected.
5,6. Four more large-acreage, whole-season definitive tests were conducted during 1998 in 40-, 140- and 160-acre blocks of grapes and peaches.
a. Use of puffers in disruption of mating of OLR and RM in table grapes. A 160-acre block of table grapes was supplied with 237 puffers in mid-March, 1998. OLR was contained in the can at a concentration of 2.5 mg of pheromone per puff, with puffs at 15- min. intervals throughout a 12-hour cycle starting 3 hours before mating communication begins. At the end of 150 days, OLR larval damage to grape clusters in this otherwise untreated vineyard was the same as a comparison vineyard that received one application of Cryolite and two applications of Dipel for OLR control. RM pheromone was also released from the puffers at the rate of 7.5 mg per puff during the entire fruiting season. Although mating disruption for this species may have been successfully achieved for this entire block significant numbers of RM larvae were found in grape bunches. RM males were unable to find lure and female baited traps throughout the entire season but we suspect females mated outside the pheromone test block flew in and laid eggs causing the damage.
b. Use of puffers in a 40-acre block of table grapes for disruption of OLR and RM. Eighty puffers were placed around the block of table grapes in mid-March releasing the same amount of pheromone per puff and at the same time as in the 160-acre block. After 150 days damage to grape clusters by OLR and RM was zero in the puffer block and a comparison block that received one application of Cryolite and two applications of Dipel received 3.3 % OLR damage and 8.3 % RM damage. Trap counts for OLR and RM were at zero the entire season for the puffer block as compared with the conventionally treated vineyard.
c. Use of puffers in a 40-acre block of stone fruit (plums, nectarines and peaches) for communication disruption of OLR, OFM and PTB. Eighty puffers were supplied to the orchard in mid-March with each releasing 2.5-mg of OLR, 2.5-mg OFM and 7.5-mg of PTB pheromone for 12 hours each night. After 120 days the fruit was inspected for larval damage. No damage was found in any of the fruit. This compared equally with a nearby conventionally treated block that received Imidan and Dipel pesticides. Trap counts of male moths captured in lure baited traps were low the entire season as compared with the conventionally treated orchard nearby.
d. Use of puffers for disruption of OLR, OFM and PTB in a 140-acre block of peaches. Puffers were supplied to the block in mid-March that released 2.5-mg OLR, 2.5-mg OFM and 7.5-mg of PTB per puff. Each puffer was set to puff for 15 minutes starting 3 hours prior to the onset of mating communication and run for 12 hours. There were 220 machines put around the orchard. After 120 days fruit was inspected for larval damage prior to harvest of each variety. No damage was detected in any researcher conducted damage counts. USDA inspectors detected 0.01% damage in the samples taken when the fruit was received at the processing plant. This compares with a conventionally treated comparison orchard. The grower made no insecticide treatment for worm damage throughout the fruiting season. Trap counts using lure-baited traps in the orchard were at zero the whole season compared with extremely high counts in the conventionally treated orchard.
7. We sample for larvae infestation to fruit in transects, with sampling rows extending from border to border through the center of the field. Through the use of this technique we have estimated that penetration of OLR mated females into a puffer treated block is only 20 meters. However our failure to disrupt OLR mating in the 40-acre block in 1997 and RM indicates some conditions moths of these species may penetrate into orchards and vineyards. After a more detailed literature search of RM pheromone it was discovered the total RM pheromone complex has never been fully researched. We have discussed this finding with other researchers and interested commodity groups who are in the process of finding the correct pheromone complex.
8. Dissemination of Findings: We have been interviewed on 17 occasions by farm magazines and newspapers, 1 radio station and 1 TV station in 1996, 1997 and 1998. The stories have raised interest in growers about puffers and their potential use in moth communication disruption. We have participated in fourteen grower-oriented conferences to an audience of over 1000 growers, PCA’s and regulatory people.
At the end of the three-year project the system is ready for a limited commercialization with a doubling of potential users each year. As registrations become available and use increases the ultimate cost of this system will decrease.
Positive benefits of Impacts: Because Lepidoptera often represent the key pests of a crop, the ability to withhold hard pesticides applications has obvious benefits. Fewer broad-spectrum pesticides treatments enable the establishment of biological controls and free the grower from reliance on pesticides. With fewer pesticide treatments a resurgence of beneficial insects is likely and pesticide resistance is reduced. The implementation of a puffer pheromone disruption system can reduce 2 or 3 pesticide applications o Imidan and Lannate each year.
Ultimately puffers will be comparable to or less expensive than other means of disseminating pheromones in orchards and vineyards. Individual puffers will cost $40.00 and will last 5 years. Because puffers are used at great separations in the field the cost of placement and maintenance is low. One man can place puffers around a 40-acre block in about 3 hours. The major expense will be the pheromone chemicals, which the price will be reduced as the usage is increased.
a. Changes in Practice: Paramount Farming Company, Bakersfield, CA has applied for registration for a number of pheromones for use in puffers and received 2 registrations. With more registrations expected before the 1999 growing season several growers are showing interest.
b. Operational Recommendations:
Registration for the pheromone chemicals to be used in puffers has been applied for. Once the chemicals are registered as pheromone by their manufactures then the chemicals can be registered for use in the aerosol puffer system. For some of these chemicals it may be the year 2000 or later.
c. Farmer Comment: According to Bill Chandler, with whom we conducted the 1998 40-acre peach trial, the system is as good as 2 or 3 pesticide applications or any OFM treatment available today. According to Max Jehle, PCA with Sunview Vineyards, with whom we conducted the puffers in table grapes trial against OLR; especially the OLR puffer program should be widely adopted, specifically in organic grapes.
Each of our major trials is conducted of the ranch of a producer, who becomes an integral member of the research team,, keeping his assessment of the pest situation in the communication disruption block and comparing his findings with regards to trapping and worm-count data, with us.
Farmers in attendance at:
Areas needing additional study
It doesn’t matter how far apart or close together the dispensers are as long as the concentration of pheromone needed to disrupt communication throughout the field is maintained during the period when females are actively calling for males.