Landscape effects on spatial distribution and movement of brown marmorated stink bug in peach orchards

Landscape effects on spatial distribution and movement of brown marmorated stink bug in peach orchards

Summary

The distribution and movement of brown marmorated stink bug (BMSB), Halyomorpha halys (Stål), in peach orchards was investigated. In the summer of 2012, twenty three orchards (13 in northern New Jersey; 10 in southern New Jersey), were monitored weekly for H. halys from May through August. These orchards were chosen based on differences in surrounding land use to create a gradient of landscapes. Geospatial information systems (GIS) software was used to map H. halys populations and categorize land use around orchards within each region (north and south). No H. halys were found in southern New Jersey, and low populations were found in northern New Jersey. Additionally, one orchard with confirmed populations of H. halys was monitored weekly at a finer scale by sampling every tree within the orchard. GIS was also used to create maps of this orchard to explore movement and immigration within a field. Although confounded by consistent insecticidal sprays and harvesting, the maps showed a pattern of immigration and establishment after sprays occurred and during harvest.

Objectives/Performance Targets

• Low H. halys populations in northern New Jersey orchards were observed. No H. halys were found in southern New Jersey orchards. This may be due to the rigorous insecticidal management occurring in these orchards. Low populations across the region may have also contributed to this finding.
• Land use around orchards in northern and southern New Jersey was quantified using ArcMap and data from the New Jersey Department of Environmental Protection (Fig.1). Northern New Jersey is predominantly forest while southern New Jersey is dominated by agriculture. Additional analysis of landscapes around individual orchards and analysis at higher levels of landscape classification will be conducted as analysis of the data progresses.
• Correlations between populations and land use have not yet been analyzed. This will be done in 2013. Relationships of populations to temperature data and insecticide spray schedules will also be incorporated.

• Sampling in three orchards in which 80 trees were sampled did not yield any H. halys.
• This objective’s methods were modified to increase sampling effort, and the number of sites sampled was limited to one due to time constraints. In following years, one additional site will be sampled.
• One orchard was analyzed using ArcMap. Patterns of immigration and establishment into the orchard were found (Fig. 2). BMSB individuals either fled or died after an insecticide application during the week of 7-9-12. Re-colonization within the orchard was observed, most likely through immigrants from the adjacent forested areas or nearby orchards. Harvests in the northeastern rows of the orchard created a distinct edge effect re-establishment.
• A second orchard sampled will be in 2013.

• Fruit damage was not assessed in 2012. Because assessing fruit damage at every single farm is too time consuming and expensive, assessments will be conducted at two Rutgers fruit research farms.

• This objective will be conducted with the use of paint or protein dye during the summer of 2013.

• Figure 1
• Figure 2

Accomplishments/Milestones

Field sites were selected in the spring of 2012 using peach growers participating in the Rutgers fruit IPM program. Prior to sampling, land use around orchards was assessed to ensure a gradient of land use. To demonstrate regional differences in land use, a landscape analysis in northern and southern New Jersey was conducted using GIS methods in ArcMap.
Orchards were surveyed weekly using visual and beat sampling from May through August. The numbers of eggs, nymphs and adults were counted at each site and gender determination for each adult found was attempted. This proved to be difficult, as adults are fast flyers and sometimes difficult to catch. Visual and beat sampling will continue the next two field seasons for further analysis. One issue during 2012 was the frequent use of pesticides. Timing sampling dates around spray schedules that were as frequent as twice per week became difficult. This problem will most likely continue in future years. Rutgers maintains three research facilities dedicated to fruit research, two of which will be used for sampling in future years. This will allow us to regulate the amount of pesticide used.
One surprise during 2012 was a decrease in H. halys populations in comparison to previous years. In objective 2, 80 trees in each of three orchards were sampled. Prior years of historical blacklight trap catches showed high BMSB populations throughout the region. However, sampling in the three orchards from May through late June indicated a drop in numbers or a lack of populations. Because low sampling effort at each orchard was a suspected explanation for the decrease, one additional orchard with known H. halys populations was selected for a fine-scale survey. In orchards with a known population, data regarding H. halys’ movement and reestablishment after an insecticide spray was gathered.
Objectives 3 and 4 were not completed due to the time devoted to orchard sampling. In 2013 and 2014, fruit will be sampled in two Rutgers fruit research farms to assess damage to peaches. In addition, if high populations are found, a proportion of the population will be marked with paint or protein dye to investigate movement and immigration.

Impacts and Contributions/Outcomes

Further investigation is necessary to make any conclusions. Although there were some indications that forested areas are more likely to have H. halys populations, low populations throughout the region make this difficult to prove. Analysis of subsequent years of data may further support my hypotheses. Although no study into the pesticide treatments used by growers has been conducted, some growers communicated they are focusing on spraying border rows surrounding their orchards thereby reducing the amount of pesticide present on fruit. Although this may not reduce total pesticide use, the reduction of pesticides on fruit is a start. By the end of this project, the hope is that pesticide use can be limited to individual orchards or sections of the orchards that are most susceptible to infestation by BMSB.
This research was presented at the Entomological Society of America meeting in Knoxville, TN in November 2012.

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