Mating disruption for the management of oriental beetle in ornamental nurseries: A research and extension effort

1) Test the efficacy of different rates of the oriental beetle sex pheromone with ChemTica bubble dispenser in commercial nurseries.

Pheromone efficacy study was conducted in 4 nurseries in New Jersey. Pheromone dispensers were deployed on June 13, 2008 after empting the pheromone traps for pre-treatment count. As shown in Table 3 and Fig 1-4, male oriental beetle captures among various treatment plots were not significantly different prior to placement of disrupters. Post-treatment trap captures were significantly lower in plots treated with pheromone dispensers compared to trap captures in untreated control plots. There were very few male adults collected in the pheromone traps with either 0.5 gram per acre or 1.0 gram per acre comparing hundreds or even thousand male oriental beetle catches in the control plots (Fig 1-4). Only exception was observed in Halka nursery where 0.5 gram of pheromone dispenser deployment still left some males trapped in the collection traps (Fig. 3). This indicated that 0.5 – 1.0 gram per acre of pheromone deployment can almost completely confuse males in searching for females. Males were not able to locate traps with 30 g pheromone in the treated plots. There is no significant difference between 0.5 gram and 1.0 gram of active pheromone ingredient on adult male catches.

For the year 2009 and 2010, similar trends were observed for the adult male beetle pheromone trap catches as that in 2008 (Fig 5, 6, 7). Few male beetles were caught from pheromone treated plots in Cream Ridge in both 2009 and 2010, as well as Overdevest in 2010 after the dispenser deployments (Fig 5, 6, 7).

Pheromone mating disruption efficiency was also measured by placing virgin females in the plots for 3 days to determine if the males can discover the virgin females when provided a treatment. Virgin female adults attracted many more males in the field where no pheromone dispensers deployed (control plots) comparing those plots with pheromone dispensers (0.5 gram/acre or 1.0 gram/acre) in all four nurseries in 2008. By doubling the pheromone dispensing rate from 0.5 gram per acre to 1.0 gram per acre, about twice as many males lost the orientation in the high dose treatment field (1.0 gram/acre) (Table 4) (Fig. 8). Similar trend was observed in 2009 and 2010 when only 1.0 gram of active pheromone ingredient was used comparing to none pheromone control. In control fields, one virgin female attracted as many as 25 males in 2009 (Fig. 9) with an average of 0.35 males per virgin female in 2010 (Fig. 10). Virgin females attracted almost no males in the pheromone treated fields (Fig. 9, 10).

However, the mating disruption efficiency was not consistent to the number of male adults interrupted when measured by average numbers of eggs produced by individual females. Females from control plots produced more eggs in Hidden Lake and Halka nurseries comparing to the pheromone treated plots, but not in the County Line and Carl Mehaffey nurseries (Table 5) (Fig. 11). The fecundity may be a function of many factors rather than just availability of males. A minimum number of males may be enough for a successful mating required by egg production. This may explain reduction of males did not result in a low egg production by females placed in the field.

2) Adult dispersal behavior determination
Black light trap: Oriental beetle adult disperse flight behavior was monitored by 2 black light traps at Rutgers Hortfarm II, New Brunswick, New Jersey during June 10 – July 30, 2008. As shown in Figure 14, both male and female adults fly during the trap season. However, number of females caught in the light trap was much less than males. Adult oriental beetle peaked in the last week of June (Fig. 14) in central New Jersey, which was similar to the peak monitored by pheromone traps (Fig 1-4).

Marker-recapture: A marker-recapture experiment was conducted at Rutgers Turf Farm, Adelphia, New Jersey to determine the male oriental beetle response distance to different pheromone concentrations of each lure at 10 g, 30 g, 2 mg, and virgin female as standard control. Male adults can detect female pheromone from 200 feet when the lure has more than 10 g pheromone. Males can detect live virgin female from 100 feet. The efficient detect distance depends on pheromone concentration placed in the trap (Table 6) (Fig 15-18).
3) Determine the susceptibility of various ornamental plants to oriental beetle.

Host plant species susceptibility was determined by plant mortality both above ground and root damage. Host plant above ground mortality % varied significantly between plant species (F4, 179 = 15.03, P = 0.0001). Average above ground mortality was 33.75% for Pieris and 26.06% for Ilex. While Arborvitae (4.17%), Azalea (0%), Boxwood (0%) showed limited above ground damage. No significant difference was detected between oriental beetle larvae density (0, 20, 40 grubs per plant) on the above ground plant mortality (F2,179 = 1.51, P = 0.2248) (Fig. 19).

Host plant root mortality varied significantly between host plant species and OB grub densities (F4, 179 = 7.33, P < 0.0001 for host plant species; F2,179 = 12.93, P < 0.0001 for grub density). Root damages were significantly higher in Pieris (37.78%), Ilex (35.97%), and Azalea (32.36%) than in Arbovitae (20.28%) and Boxwood (14.17%). The average root damage % (33.58-34.92%) was significantly higher when with 20 or 40 grubs per plant than control (15.83%) plant without any grubs inoculated (Fig. 20).

4) Extension
Attached is a copy of one of the surveys we attempted with the growers. Over the course of the project we gave talks at the annual South New Jersey Nurseyrmens meeting as well as at least two night meetings held on farms. Summed up, the number was closer to 250 growers that I talked to.

Of the 20 odd growers who filled out the form none were suitable for analysis. With that in mind I tried Survey Monkey for distributing the questionare. The rationale was they would respond from the privacy of their office. Again no usable results. Of the growers I spoke with privately they were enthusiastic about the prospects but deployment on the farm remained an issue.

For Objectives 3-5 we were limited by acreage used in the EPA permit but where we were able we enlisted grower participation in the dispruption phase. The Final Milestone: Due to the pheromone not being yet commercially available no growers are emplying this technology. Another major deterrent to adoption is how to actuall use the disruption on a whole farm basis. I am still presenting the results to growers and am slated for another talk in October 2011 in Cumberland County NJ.

• Fig. 5. Male oriental beetle pheromone trap catches – Cream Ridge, NJ 2009
• Fig. 13. Oriental beetle grubs in potted plants (Sept. 2010)
• Fig. 17. Male adult oriental beetle attracted to granule pheromone trap
• Survey for nurserymen
• Fig. 3. Male oriental beetle pheromone trap catches – Halka Nursery, NJ 2008
• Fig. 8. Male adults attracted to each virgin female – New Jersey, 2008
• Fig. 18. Male adult oriental beetle attracted to a virgin female
• Table 5. Mean eggs produced by virgin females placed in the treatment plots, NJ 2008
• Fig. 1. Male oriental beetle pheromone trap catches – Carl Mehaffey, NJ, 2008
• Fig. 4. Male oriental beetle pheromone trap catches – Hidden Lake, NJ 2008
• Fig. 6, Male oriental beetle pheromone trap catches – Cream Ridge, NJ 2010
• Fig. 9. Males attracted to virgin female Cream Ridge, NJ 2009
• Fig. 10. Males attracted to virgin female – New Jersey 2010
• Fig. 12. Oriental beetle offspring grubs (Cream Ridge, NJ, Sept. 20, 2009)
• Fig.14. Oriental beetle light trap catch in Hortfarm II, New Brunswick, 2008
• Fig. 15. Male adult oriental beetle attracted to 10 µg pheromone trap
• Fig. 19. Above ground damage with different oriental beetle larval density
• Fig. 20. Host plant root damage (%) with different oriental beetle larval density
• Table 4. Mean male adults attracted by virgin females placed in the treatment plots
• Table 3. Male adults collected by using monitoring pheromone traps
• Table 6. Mark-recaptured of male adults in response to the female pheromones
• Fig. 2. Male oriental beetle pheromone trap catches – County line, NJ 2008
• Fig. 7. Male oriental beetle pheromone trap catches – Overdevest, NJ 2010
• Fig. 11. Mean eggs produced by virgin females placed in the treatment plots, NJ 2008
• Fig. 16. Male adult oriental beetle attracted to 30 µg pheromone trap