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

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

Summary

Note to the reader: A series of data charts accompany this report, and can be requested from Northeast SARE. When making a request, please reference project number LNE07-253.

Progress to date:

We have made most of out program goals to date as far as testing the rates of pheromone for disruption and reduced trap catch. We have established a rigorous test for plant respose to beetle feeding on roots which will be evaluated next fiels season. We have shown that females do disperse more than was reported. The extension component will be well underway by the next field season

Objectives/Performance Targets

Performance target: Of the 400 nurserymen educated on mating disruption, at least 18 will adopt this technology by the end of the project. In so doing, participants will reduce their insecticide use.

Research and extension component

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

The experiment was conducted in commercial nursery farms in New Jersey in 2008 to evaluate the efficacy of ChemTica pheromone point-source dispensers containing the major component (Z)-7-tetradecen-2-one for oriental beetle mating disruption.

Treatments were replicated in four different nursery farms: Hidden Lake Nursery, Cream Ridge; Carl Mehaffey Nursery, Bridgeton; County Line Nurseries, Bridgeton; Halka Nurseries, Bridgeton, New Jersey (1 farm = 1 replicate) and each treatment within farm (plot) was at least 100 x 100m (2.5 acres). Dispensers were placed in an evenly-spaced grid in nursery on 13 June, 2008.

In each plot, three Japanese beetle sex pheromone traps (Trécé, Salinas, CA) baited with 30 µg of oriental beetle sex pheromone were placed and monitored weekly to determine male populations. Traps were placed on June 4, 2008, prior to placing dispensers to obtain number of beetles before treatment.

Mating rates were assessed in each plot by placing screened cylinders containing a virgin female (virgin females were obtained by collecting larvae from infested turf grass and rearing them to adults). Cylinders have been designed to allow males entering but preventing males and females from exiting. Cages (280 virgin females) were placed in plots 4 times over a 2-week period: at the end of June, and 1st-2nd week in July. These cages were placed in plots for 3 nights and then retrieved to determine male presence. Retrieved females were placed in 30 ml rearing cups with moist sand and allowed to lay eggs to determine the female mating success.

2) Adult dispersal behavior determination
Black light trap: Oriental beetle adult disperse flight behavior was monitored by 2 light traps set up at Hort Farm II, New Brunswick, New Jersey during June 10 – July 30, 2008. Traps were visited daily to count the numbers of male and female oriental beetle adults.

Male marker-recapture: A marker-recapture experiment was conducted on the Rutgers Turf Farm, Adelphia, New Jersey during the adult peak season to determine the distance male oriental beetle travel in response to different pheromone rates and/or sources.

Males fresh collected from oriental beetle pheromone traps (with 30 µg) on the day of marker releasing. 100 male oriental beetle adults were marked with gloss enamel Testors® model paint for each releasing treatment according the treatments (5 distances and 4 pheromone types). Individual virgin females were placed in a mesh cage that was attached to the beetle trap as regular pheromone lure. Marker-recapture treatments were repeated 3 times on July 1, July 2, and July 3, 2008. Male beetles were released in the late afternoon and collection traps were empted next afternoon for a 24 hours collection.

3) Determine the susceptibility of various ornamental plants to oriental beetle.
Experiment was conducted at Cream Ridge, New Jersey. Oriental beetle larvae were inoculated in the 10 gallon pot-in-pot plants on September 20 and 21, 2008 to test the host plant susceptibility in 5 host plant species. Buxus (Boxwood), Rhododendron obtusum ‘Hino Crimson’ (Hino Crimson Azalea), Ilex (Japanese Holly), Thuja (Arborvitae), and Rhododendron. Each plant was inoculated with 0, 20, or 40 oriental beetle larvae. Six plants per treatment and repeated once. Plant performance of the infested plants will be assessed susceptibility in May 2009 with parameters of height, above and below ground fresh biomass (weight), dieback percentage, and discoloration.

Extension

We are developing the survey for nurseryman to fill out. This will be done by Spring 2009. The scouting protocols are being developed and nurserymen will be enlisted for the scouting program

Accomplishments/Milestones

Efficacy of rates

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, 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. Only exception was observed in Halka nursery where 0.5 gram of pheromone dispenser deployment still left some males trapped in the collection traps. This indicated that 0.5 – 1.0 gram per acre of pheromone deployment can almost completely confused males in searching for females.

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).

However, the mating disruption efficiency was not consistent when measured by average numbers of eggs produced by virgin 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). The fecundity may be a function of many factors rather than just availability of males. Only a minimum number of males may be required for 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 light traps at Hort Farm II, New Brunswick, New Jersey during June 10 – July 30, 2008. Both male and female adults fly during the 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. 1), which was similar to the peak monitored by pheromone traps (Fig 1-4).

Marker-recapture: A marker-recapture experiment was conducted on the Rutgers Turf Farm, Adelphia, New Jersey to determine the distance of male oriental beetle travel in response to different pheromone rates 10 µg, 30 µg, granule, and virgin female as a standard. Male adults can detect female pheromone from 200 feet distance when pheromone lure is more than 10 µg. Males can detect live virgin female from 100 feet. The efficient detect distance depends on the strength of the pheromone placed in the trap. Males can detect female sex pheromone lure from 200 feet (Table 6).

3) Determine the susceptibility of various ornamental plants to oriental beetle.
Experiment was conducted at Cream Ridge, New Jersey. Oriental beetle larvae were inoculated in the 10 gallon pot-in-pot plants on September 20 and 21, 2008 to test the host plant susceptibility in 5 host plant species. Buxus (Boxwood), Rhododendron obtusum ‘Hino Crimson’ (Hino Crimson Azalea), Ilex (Japanese Holly), Thuja (Arborvitae), and Rhododendron. Each plant was inoculated with 0, 20, or 40 oriental beetle larvae. Six plants per treatment and repeated once. Plant performance of the infested plants will be assessed susceptibility in May 2009 with parameters of height, above and below ground fresh biomass (weight), % dieback, and discoloration.

Impacts and Contributions/Outcomes

Although we have made excellent progress we think it is premature to establish a firm outcome.

Collaborators: