Christopher B. Riley 1

Designing a Sustainable Landscape:

The Distribution of BMSB and the Implications for a Pest Resistant

Environment

Introduction

The Brown Marmorated Stink Bug, Halyomorpha halys (Stål), is a non-native,

invasive species first seen in the United States in the mid 90’s [2]. Less than two decades

later, this Asian pest has been detected in over 35 states (Fig.1) and has become a

significant agricultural pest in several Mid-Atlantic States, including Maryland,

Pennsylvania, and Virginia [1]. A polyphagous herbivore in Asia, BMSB is known to use

a range of host plants, including corn, soy bean, wheat, a variety of fruits, and ornamental

trees and shrubs [4]. H. halys feeds using its proboscis, a needle-like appendage that

allows it to pierce the skin of fruit, leaves or bark, and suck out nutrients. This feeding

mechanism is responsible for poorly formed and discolored fruits and vegetables, which

can seriously affect market value [4]. In Pennsylvania in 2010, BMSB damage alone was

responsible for a loss of 25% of apple and stone fruit crop [3].

In addition to feeding on plants outdoors in summer, BMSB is a major nuisance

pest when it enters homes in autumn to overwinter. Ornamental plants in people’s

landscapes serve as hosts for BMSB that will enter their homes. By understanding which

plants serve as hosts and which do not, BMSB resistant landscapes can be designed. This

will greatly reduce the number of BMSB entering homes in autumn and reduce the need

for insecticide applications indoors and outside. By reducing the need for chemical

interventions, urban landscapes will be made more conducive to ecosystem processes and

more sustainable. Our research focused on identifying BMSB host use using a wide

variety of native and ornamental plants in a ornamental plant nurseries in Maryland. Our

specific research goals were the following:

1. To identify the patterns of host use by adult and juvenile BMSB with respect to a wide

variety of species and cultivars or woody landscape plants

2. To determine whether there is a preference for Asian or non-Asian species of plants

3. To determine whether there is a preference for Angiosperms or Gymnosperms

4. To identify any spatial distribution patterns, such as edge effects, and how the

composition of neighboring field use play a role in colonization

5. To better understand how the number of generations and speed of life cycles can

fluctuate on different ornamental plants

Materials and Methods

The study site used in 2011 was Raemelton Farm in Adamstown, MD and in 2012

a second nursery was added, Ruppert Nurseries in Laytonsville, MD. Each location has

numerous fields that were sampled at regular intervals, every other week, throughout two

growing seasons. For each row within a field, the three exterior trees facing the edge

were sampled (Fig. 3). After those three were sampled, five were skipped, and then three

interior trees were sampled. This ultimately provided data on the edge of the field and the

interior so that the spatial distribution as well as the distribution across the fields could be

considered.

National Socio‐Environmental Synthesis Center

Christopher B. Riley 2

For each tree, a fifteen second evaluation was performed (Fig. 3). If no BMSB of

any life stage were seen, the tree was given a zero value. If any life stage was seen, a one

minute count was performed with a tally of each life stage (egg mass, early nymph, late

nymph, or adult) seen on bark, leaves, or fruit. This data allowed us to track the

development and speed of the life cycle throughout the season.

Results

The data collected from the 2011 field season is complete (whereas the 2012 data

is still being collected) and therefore provides the best tools to address the research

objectives. Of the 178 cultivars sampled, 150 were used by some life stage (Fig. 1).

Almost one third of the plants sampled were used by all three life stages, adults, nymphs,

and eggs, indicating that BMSB is a fairly generalist insect in that it can lay eggs, feed,

mature, and mate, on a broad range of plants. Twenty-eight cultivars were not used by

any life stage. Pending confirmation from the 2012 field season, this finding could

provide some of the best information on which cultivars to use when attempting to design

BMSB resistant landscapes.

Based on data from 2011, there was a slight trend for greater numbers of stink

bugs to be present on non-Asian cultivars, however 2012’s data will help to confirm or

challenge this finding (Fig. 2). A stronger trend was observed in patterns of use between

Angiosperms and Gymnosperms (Fig. 3). Angiosperms were clearly favored hosts for

egg masses, nymphs, and adults, likely due to the fact that they provide broad, flat leaves

for egg laying, often have fruit, and are easier to maneuver on then evergreens.

In 2011, Raemelton Farm was adjacent to a sod farm on the side of Field 1 and a

soybean field to the side of Field 5. Soy is a known food source for BMSB, and

consequently, there were always high densities around the soybean border. The large-

scale findings indicate that Field 5, which always had the highest numbers, acted as a

entry point to the rest of the nursery (Fig. 4). Similarly, and on a smaller scale, the edge

trees in four out of five fields acted as a border to the interior, with lower average

numbers for the interior three trees. Not only does this suggest that neighboring field

usage plays a role, but it suggests that there is in fact an edge effect, which could

ultimately be exploited in landscape design.

The preliminary findings in 2012, which used a slightly different design, do not

confirm these findings (Fig. 5). The graph shows that field 6 had the fewest of any field,

however there are many possible reasons for this and it is hard to judge without the full

summer’s data.

In order to assess the frequencies of each stage as the summer progressed, all of

the numbers for each reading were added from both sites. Table 1 shows the clear

increase of egg masses, early instars, and late instars as the summer progressed. Though

reading 5 was not included, findings indicated that it was going to have the largest

number of active BMSB yet.

Discussion

We were fairly surprised to find that of the total 178 cultivars sampled in the

summer, there were only 28 that never supported any stage of BMSB.. This is a testament

to the polyphagous nature of this pest and why more research needs to be done on

indentifying cultivars that are not favorable. By replicating the survey and expanding it in

Christopher B. Riley 3

2012, we will either expand, shorten or solidify the list of hosts used by BMSB. We will

be able to further evaluate the findings on preference for Asian vs. non-Asian cultivars.

In this type of study, which is largely observational, replication is especially important to

confirm what has been seen.

In combination with the findings on Angiosperm vs. Gymnosperm preference,

researchers may now begin to take steps toward defining certain species as truly BMSB

resistant. This will be especially important in designing BMSB resistant landscapes.

Information on the edge effect will help landscape and nursery managers know where

BMSB populations are the highest. This can help guide management decisions such as

which plants to treat. Confirming that crops like soybeans can act as a source of invading

BMSB is important and carries significant implications for nursery and farm owners, who

could then restructure their fields to minimize movement by these invasive insects.

Conclusions

The main objectives during my internship with the National Socio-Environmental

Synthesis Center were to further understand how knowledge on patterns of the host use

and spatial distributions of BMSB could be used to design more sustainable landscapes.

These objectives were met through regular readings of multiple fields in two different

ornamental nursery settings.

This study will likely continue into 2013 to help solidify the findings presented

here and help direct further questions and projects. The next steps will include

manipulating variables and testing the rolls of co-evolution and defense-free space in

structuring host use.

As an intern with SESYNC, I was taught to consider all of the stakeholders that

could be affected by the proliferation of an invasive species that poses a threat to

agricultural and citizens. From this starting point, I am better able to assess how such a

problem could be seen and what a solution may look like to the many different parties. In

this case, most people benefit from the control of BMSB, however doing so effectively

involves the collaboration of research institutions, government organizations, members of

the agricultural community, and even homeowners.

One form of “Actionable Science” that can help foster this is the Agricultural

Extension program. Created originally as a tool to allow professionals to disseminate

information to those who need it most in the field, it has now become a huge network of

individuals all striving for the best practices in the field of agriculture and its associated

disciplines. Actionable science in this context can be seen when the research I have

performed, such as identifying resistant cultivars, is disseminated to farmers and

homeowners who can then adjust their landscape to resist this invasive pest. It is only a

part of the puzzle in the bigger picture of Integrated Pest Management, however when the

system works as a whole, actionable science is created and implemented.

Christopher B. Riley 4

References

[1] BMSB IPM Working Group. "Current Distribution of BMSB in the United States."

Animal and Plant Health Inspection Service. United States Department of Agriculture, 30

Nov. 2011. Web. 27 July 2012.

<http://www.aphis.usda.gov/plant_health/plant_pest_info/bmsb/downloads/Distribution.

pdf>

[2] Hamiliton, George C. "Brown Marmorated Stink Bug." American Entomologist

(2009): 19-20. Web. 27 July 2012

[3] Murray, Rheana. "Stink Bugs Invading America." NY Daily News. N.p., 27 Mar.

2012. Web. 27 July 2012

[4] Welty, Celeste, David Shetlar, Ron Hammond, Susan Jones, Barbara Bloetscher, and

Anne Nielsen. "Brown Marmorated Stink Bug." Fact Sheet: Agriculture and Natural

Resources. The Ohio State University, 2008. Web. 27 July 2012

Christopher B. Riley 5

Figure 1. Courtesy of the USDA – APHIS [1]

Christopher B. Riley 6

Figure 2. Representation of a typical three rows in a typical field, where every box is a

tree. Three orange boxes represent the threes trees being sampled on the edge and the

interior.

Christopher B. Riley 7

Figure 3. Standard procedure for data collection. Represents the decision tree for each

new tree the observer arrives at.

Christopher B. Riley 8

Figure 1. Host use at the Cultivar level in 2011. Center value represents approximately

1/3 of all cultivars are used by each stage. “28” value at the bottom right is the number of

cultivars not used by any stage.

Christopher B. Riley 9

Figure 2. Findings in 2011 with regards to BMSB host use for Asian or non-Asian

cultivars. Findings indicate greater use of non-Asian cultivars.

Christopher B. Riley 10

Figure 3. Findings in 2011 with regards to preference for Angiosperms vs.

Gymnosperms. Angiosperms are the preferred cultivar type for laying eggs, maturing,

and feeding.

Christopher B. Riley 11

1 2 3 4 5

Eggs

Field

Egg M

ass S

easonal A

vera

ge

0.0

00.0

20.0

40.0

60.0

80.1

0

Core Edge

1 2 3 4 5

Nymphs & Adults

Field

Nym

ph +

Adult

Seasonal A

vera

ge

01

23

4

Core Edge

Figure 4. 2011. Findings with respect to spatial distribution at Raemelton Farm. Largest

numbers were seen in field 5 due to the proximity to the soybean crop. Within each field

(except for 4), there was a noticeable difference between the edge and the interior of the

field, further demonstrating an edge effect.

Christopher B. Riley 12

Figure 5. 2012. Preliminary counts of BMSB at Raemelton Farm, including readings 1-4.

Field 2 Field 3 Field 4 Field 5 Field 6 Corn

Christopher B. Riley 13

Table 1. Total measurements seen across both Ruppert and Raemelton for the first 4

readings of 2012. Chart shows an increasing trend in the number of egg masses, early

instars, and late instars, with the overall trend of an increase in active BMSB.

Date Reading Egg Masses

Newly Hatched

Early Instars

Late Instars

Adults Active

5/28-6/8 1 7 11 69 8 223 300

6/11-6/22 2 5 26 245 3 152 400

6/25-76

3 11 38 423 63 62 548

7/9-7/20 4 44 21 862 272 209 1342