The sweltering summer of 2017 has a silver lining. When the temperature rises above 104, brown marmorated stink bug population growth is significantly slowed, reported Debbie Arrington in the Sacramento Bee.
An invasive pest from Asia, brown marmorated stink bugs showed up in midtown Sacramento in 2013. Their spread to commercial crops has been a concern. The stink bugs feed on dozens of California crops, including apples, pears, cherries, peaches, melons, corn, tomatoes, berries and grapes, said Chuck Ingels, UC Cooperative Extension advisor in Sacramento County. Feeding on fruit creates pock marks and distortions that make the fruit unmarketable. In grapes, berries collapse and rot increases.
In 2014 and 2015, the bugs' numbers continued to rise. In early 2016, Ingels feared a population explosion, but a heat wave in July, with seven days at 100 degrees or higher, plus two days at 104, wiped them out.
“This year, BMSB started off at historic lows (since 2013),” Ingels said. “Then, the June heat wave hit and the population that was there plummeted. Most of our trap counts for the last few weeks have been at or near zero, whereas there's usually a peak in June. So, it seems to be proof that temperatures over 100 for extended periods reduces the population – probably especially eggs and nymphs."
Ingels and UC Davis entomologists are studying the connection between high heat and stink bugs in the lab, where the pest is exposed to extreme temperatures. One hour at 113 degrees killed all the bugs, but mortality was also high over 104 degrees.
Chuck Ingels, UC ANR Cooperative Extension advisor in Sacramento County, said BMSB was first spotted in 2013 in Sacramento and each year the numbers have grown. This year, the warm spring gave BMSB a head start, portending significant population growth in August and September 2015.
"We're very concerned about tree crops, tomatoes, peppers, corn, beans and other crops," Ingels said. On a bright note, he said California farms do not have forests surrounding them like farmers back East, where growers have been dealing with BMSB since the the mid-1990s. "BMSB is an arboreal species. They live in trees and then come into the farm. We're not sure how much of a problem it will be on farms here (in California)."
Ruyak asked whether any control solutions can be found in the pest's native territory or from farmers back East.
"Growers are using pesticides back East," Ingels said. "There is a parasitoid from China that is under study in labs to see if they pose a problem for native stink bugs and other bugs."
One possible solution for dealing with the pests in gardens is planting sunflowers. Because BMSB are strongly attracted to sunflowers, they may draw the pests away from other crops and allow gardeners to monitor the BMSB presence. On the other hand, sunflowers may actually attract BMSB to the garden, where they could feed on vegetable crops.
BMSB feeds with a mouthpart called a "proboscis," stinging developing fruit 1/4 to 3/8 inch deep and sucking out its juices. As the fruit ripens, it hardens and deforms, becoming inedible.
Read more about BMSB, how to identify it, and methods to manage it around homes and gardens in the UC IPM Pest Note: Brown Marmorated Stink Bug.
"Wow, I'm being overwhelmed with calls about brown marmorated stink bugs getting into people's home, as well as restaurants and businesses," said Chuck Ingels, UC Cooperative Extension advisor in Sacramento County. "It's that time of year again!"
When days get shorter and cooler, the BMSB start looking for a place to spend the winter. Frequently, that's inside homes and buildings.
Ingels told the reporter he is keeping track of the BMSB invasion. Residents are asked to fill in an online survey to report BMSB finds. For identification help, residents may deliver BMSB in a sealed plastic bag or container to the UCCE office, 4145 Branch Center Road, Sacramento, or they can email clear photos to email@example.com.
Ingels said fairly large populations of BMSB have been found in Citrus Heights near Auburn Boulevard and River Park north and west of CSU Sacramento.
"Most of the others are single finds," he said.
For more information on BMSB identification and management, read a Pest Note posted by the UC Integrated Pest Management program.
Chuck Ingels, UC Cooperative Extension advisor in Sacramento County, told the reporter homeowners with traditional green lawns may soon have no choice but to let them go brown. An average of 50 to 60 percent of a household's water consumption goes to outdoor use, which includes the landscape. He envisions a future in which lawns go dormant in winter and in summer, if watering is not allowed.
“The water bills are going up,” Ingels said. “I think we're going to start seeing more and more people opt for a brown lawn. I think it could become more traditional.”
If some water is available, there are less thirsty alternatives to traditional lawns that can provide a similar effect. Ingels has experimented with meadow-like buffalograss and dune sedge as alternatives. For example, UC Verde buffalograss, released in 2003, was bred for the California climate by UC researchers. It needs only infrequent mowing, uses half the water of tall fescue and is disease and pest resistant.
Other options are drought-tolerant native species like carex and bentgrass. These can be used for the meadow effect if not mowed, or mowed regularly for a more traditional look.
“A single lawn sprinkler can use as much water as taking a shower,” Ingels said. “Many people don't even know where their (sprinkler) controller is. They are often hidden behind boxes or bicycles in the garage.”
The press conference was held jointly by the California Department of Water Resources, UC Cooperative Extension and UC Davis. The speakers noted that every drop of water saved by not watering already moist lawns will ensure there's more water when warmer months arrive. As part of the event, Ingels demonstrated a simple test to determine lawn moisture.
He easily pushed a flat-head screwdriver into the lawn up to its handle, indicating the soil beneath the surface is moist. If it doesn't sink in all the way or needs pressure, the lawn may need water.
In the coming months, there are many more strategies that can be employed to make the most efficient use of water placed on landscapes, which represents more than half of home water use.
- Determine your home sprinklers' output by conducting a catch can test
- Program the controller to deliver water in short increments broken up with time for the water to soak into the ground
- Use drip irrigation for plants and trees
- Cover the soil with mulch to reduce evaporation from the soil surface
Read more here: Conserve water with proven landscape irrigation strategies
Additional home and ag water conservation resources are available from the UC California Institute for Water Resources, http://ucanr.edu/drought.