Meet the Researcher: Byju Govindan

Dr. Byju Govindan (left) is part of an MITPPC-funded team, led by Extension entomologist Bill Hutchison (right), working on the early detection, forecasting and management of the invasive brown marmorated stink bug.

What is the brown marmorated stink bug, and where is it found?

The brown marmorated stink bug (BMSB) is a non-native sucking insect pest with more than 170 host plant species – apples, corn, grapes, soybeans and more. BMSB was first detected here in Minnesota in 2010.

The insect is consistently detected from early spring to late fall, with most growing populations confined to the seven-county metro region. BMSB benefits from global warming and the "urban heat island" effect that causes warmer winter temperatures in more heavily developed areas like the Twin Cities. Because of the wide range of plants they can feed on, a lack of natural enemies and the insect's hardy ability to survive the cold, populations continue to grow and expand to new areas of Minnesota and the Midwest.

Why is the brown marmorated stink bug a problem?

BMSB feeds voraciously on many important field crops, fruits and vegetables, sometimes to the point of total crop loss. Infestations in our area have so far stayed below economically damaging levels, but this pest is an emerging threat to the state's agricultural industries.

The adults also enter a resting phase during the winter, often seeking shelter in homes, barns and other buildings in massive numbers (similar to the Asian lady beetle). For this reason, BMSB is becoming a serious nuisance pest to homeowners.

How will your research help?

I am helping to develop a "degree-day model" for BMSB. Insects like BMSB do not grow from egg to adult according to simple calendar days; instead, the stages of insect development are highly dependent on ambient temperature changes, according to temperature accumulation over time (measured in units called 'degree-days'). Degree-day models can help Minnesota farmers better time important management activities, such as pest scouting or even treatment decisions, if and when necessary.

Our model was developed using both laboratory and field research, for the most accurate predictions. It showed BMSB population growth occurring between 68-86 degrees F, with the best growth conditions occurring around 80 degrees – right in the center of Minnesota’s current and projected average summer temperature ranges. This means that BMSB populations are very likely to expand at the northern edge of their range in the Midwest.

I'm paying special attention to how BMSB growth occurs in fall populations, as this is the time frame for which fruit crops like raspberries and wine grapes are most vulnerable to damage, or when "bug contaminants" may occur, which can affect a final, marketable product.

This model is also the first to chart how BMSB reproduction and lifespan can change with temperature in Minnesota. Right now, our research suggests that Minnesota-acclimated BMSB develop faster and survive more often (higher survival rate) than their counterparts from other regions of the US. BMSB populations here also go through more than one generation. This work is specific and accurate for the Minnesota BMSB population – meaning better population predictions for growers in our area.

What can people do to help fight BMSB in Minnesota?

BMSB is only an emerging threat to Minnesota agriculture, so far. We are hopeful we can keep populations below a damaging level via our proactive research and management recommendations.

If you spot BMSB in a building, field, vehicle or elsewhere, we encourage you to send a photograph (a cellphone shot is fine) to the Minnesota Department of Agriculture via the "Arrest the Pest" program, and/or to the University of Minnesota Department of Entomology. People can also reach out to their County Extension offices.

To report a confirmed BMSB detection, or to view locations where BMSB has been detected to date in Minnesota and elsewhere, visit the national invasive species reporting database EDDMapS.

The University of Minnesota Extension IPM Program, in partnership with the Minnesota Invasive Terrestrial Plants and Pests Center and Purdue University, have also developed a free IOS and Android app, Midwest Stink Bug Assistant, to help farmers, crop consultants and the general public identify and distinguish BMSB from other common stink bugs in Minnesota. If you are interested in learning detailed information and ways to proactively manage the pest, I encourage you to visit www.stopBMSB.org.

What drew you to work with invasive species?

I’ve had a long-term interest in entomology, insect ecology and integrated pest management (IPM). But the opportunity to work with invasive species is particularly intriguing. Invasive species cause huge losses both to agricultural and natural ecosystems by affecting crop production and biodiversity. They impact our lives in unforeseen ways.

The annual cost of invasive species is estimated to be roughly $1.4 trillion globally, $120 billion in the US and $3 billion in Minnesota. I have the opportunity to uncover new information about how invasive species like BMSB adapt to Minnesota conditions, and to be one of the first responders addressing the concerns of agricultural stakeholders. This makes me passionate about my work.

Dr. Govindan is author of a 2020 research publication in the peer-reviewed journal Insects, available online now: https://z.umn.edu/govindan.

Funding for this project was provided by the Environment and Natural Resources Trust Fund as recommended by the Legislative and Citizen Commission for Minnesota Resources.