- Author: Ben Faber
A lot of work has been put into monitoring the Brown Marmorated Stink Bug (BMSB), Halyomorpha halys (Hemitpera: Pentatomidae). It has been a major problem in many areas of the country, as well as California. Hoddle and crew did extensive trapping in the state and found some serious populations in some areas and fewer in others. Read their great story here - https://cisr.ucr.edu/blog/2013/06/17/pheromone-trapping-program-brown-marmorated-stinkbug
A recent study by Illán et al suggests a more predictive method of assessing the threat of spread across the US and California:
Evaluating invasion risk and population dynamics of the brown marmorated stink bug across the contiguous United States
Abstract
BACKGROUND; Invasive species threaten the productivity and stability of natural and managed ecosystems. Predicting the spread of invaders, which can aid in early mitigation efforts, is a major challenge, especially in the face of climate change. While ecological niche models are effective tools to assess habitat suitability for invaders, such models have rarely been created for invasive pest species with rapidly expanding ranges. Here, we leveraged a national monitoring effort from 543 sites over 3 years to assess factors mediating the occurrence and abundance of brown marmorated stink bug (BMSB, Halyomorpha halys), an invasive insect pest that has readily established throughout much of the United States.
RESULTS; We used maximum entropy models to estimate the suitable habitat of BMSB under several climate scenarios, and generalized boosted models to assess environmental factors that regulated BMSB abundance. Our models captured BMSB distribution and abundance with high accuracy, and predicted a 70% increase in suitable habitat under future climate scenarios. However, environmental factors that mediated the geographical distribution of BMSB were different from those driving abundance. While BMSB occurrence was most affected by winter precipitation and proximity to populated areas, BMSB abundance was influenced most strongly by evapotranspiration and solar photoperiod.
CONCLUSION: Our results suggest that linking models of establishment (occurrence) and population dynamics (abundance) offers a more effective way to forecast the spread and impact of BMSB and other invasive species than simply occurrence-based models, allowing for targeted mitigation efforts. Implications of distribution shifts under climate change are discussed.
https://doi.org/10.1002/ps.7113
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- Author: Kathy Keatley Garvey
Let's hear it for biocontrol.
You've seen lady beetles, aka ladybugs, preying on aphids.
But have you seen an assassin bug attack a spotted cucumber beetle?
No?
How about a crab spider munching on a stink bug?
All biocontrol, part of integrated pest management (IPM).
If you access the University of California Statewide Integrated Pest Management Program (UC IPM) website or more specifically, this page, you'll learn that "Integrated pest management, or IPM, is a process you can use to solve pest problems while minimizing risks to people and the environment. IPM can be used to manage all kinds of pests anywhere–in urban, agricultural, and wildland or natural areas."
Or, UC IPM's more in-depth definition:
"IPM is an ecosystem-based strategy that focuses on long-term prevention of pests or their damage through a combination of techniques such as biological control, habitat manipulation, modification of cultural practices, and use of resistant varieties. Pesticides are used only after monitoring indicates they are needed according to established guidelines, and treatments are made with the goal of removing only the target organism. Pest control materials are selected and applied in a manner that minimizes risks to human health, beneficial and nontarget organisms, and the environment."
Think of biocontrol as beneficial: "Biological control is the beneficial action of predators, parasites, pathogens, and competitors in controlling pests and their damage. Biological control provided by these living organisms (collectively called "natural enemies") is especially important for reducing the numbers of pest insects and mites, but biological control agents can also contribute to the control of weed, pathogen, nematode or vertebrate pests."--UC IPM
Yesterday we witnessed an incredible case of biocontrol in action.
At Bodega Bay's Doran Regional Park, Sonoma County, we spotted a great blue heron stepping stealthily through a thatch of ice plant in the Jetty campground. It was 6:30 in the morning. As campers slept in their recreational vehicles a few feet away, the great blue heron just kept stepping silently through the ice plant. One step. Another step. And another.
And then it happened. Its long sharp beak speared a rodent. Yes, they eat rodents. It crunched the body from head to toe, breaking the bones, and then swallowed it whole.
Not a pretty picture, but a simple case of biocontrol, compliments of a hungry heron.
- Author: Ben Faber
Stink bugs of various species have been an issue on avocado and citrus for many years. Not always an issue, but occasionally they can reach damaging proportions.
http://ucanr.edu/blogs/Topics/index.cfm?start=4&tagname=stink%20bug
For stink bugs to attract a mate or to communicate that they have found food, they use their own chemical language: pheromones.
Virginia Tech researchers have discovered insights into this chemical language, which can be used to develop alternative pest controls.
"We have gained a deeper understanding of how stink bugs synthesize pheromones, and this knowledge may allow us to produce pheromones in expendable food crops - also called 'trap crops' - to lure the bugs away from cash crops," said Dorothea Tholl, a professor of biological sciences in the College of Science and a Fralin Life Science Institute affiliate.
These new environmentally friendly and sustainable alternatives to insecticides could save farmers millions of dollars.
In Virginia, crops such as grapes, sweet corn, and apples, have been under attack by the invasive brown marmorated stink bug since 2004; cabbage has also been affected, but by the harlequin stink bug. A relative, the southern green stinkbug is also a severe pest worldwide and attacks many different crops including beans and soybeans.
Tholl is interested in the chemical communication of organisms and studies how this chemical language has evolved in insects. With support by a grant from the USDA National Institute of Food and Agriculture, her lab investigates the enzymes that produce stinkbug pheromones in an interdisciplinary collaboration with colleagues at Virginia Tech and national and international institutions.
Her team's research has recently been published in the journal Proceedings of the National Academy of Science, or PNAS.
"Our recent paper provides valuable insight into our understanding of how insects synthesize complex sesquiterpene compounds that are typically used as pheromones. The work could pave the way in the future for plants to manufacture insect pheromones, which could be utilized in pest surveillance and pest management strategies, such as attract and kill," said Thomas Kuhar, a professor of entomology in the College of Agriculture and Life Sciences and a Virginia Cooperative Extension specialist.
Very little was known about the biosynthetic evolution of these insect pheromones, and the research of Tholl's team has shown that stink bugs have their own enzymatic machinery to make pheromones without receiving them from symbiotic microbes or the host plant, as was previously thought.
Jason Lancaster of Knoxville, Tennessee, a recent biological sciences Ph.D. graduate from Tholl's lab, used next-generation sequencing to identify and functionally characterize the first enzyme in the biosynthetic pathway of the harlequin bug pheromone compound.
"Pheromones for thousands of insects are known, but very little is known about the synthesis of the pheromones. This paper focuses on terpene derived pheromones from the harlequin stink bug Murgantia histrionica and encompasses many years of research. Besides the development of dead-end trap crops, this research may allow establishing "RNAi interference" type gene silencing mechanisms to disrupt the pheromone production of the insect," said Lancaster.
Lancaster also found that other stink bugs such as the brown marmorated stink bug use enzymes in pheromone biosynthesis similar to that identified in the harlequin bug. Beyond the team's current study on stink bug pheromones, the research may allow for exciting future discoveries in the biosynthesis of pheromones of other insects and their application in pest management.
Two of Tholl's graduate students, Andrew Muchlinski and Bryan Lehner, are co-authors on the paper and contributed substantially to this research.
There is commercial interest in using the genetic tools developed by Tholl's team to produce the pheromones via synthetic biology for application in the field to promote pest mating disruption.
"Overall, we are excited about the prospect that our research has the potential to develop new pest management techniques," says Tholl.
https://www.eurekalert.org/pub_releases/2018-08/vt-dch081718.php
IMAGE: For stink bugs to attract a mate or to communicate that they have found food, they use their own chemical language: pheromones.
- Author: Ben Faber
Last May/June during a hot period and soon after fruit set, avocado growers and PCAs in the Oxnard/Camarillo area were calling in about young fruit about he size of a quarter showing up with white spots. Cutting into the fruit there might only be a small black spot just below the injury. Because that's what it is, a wound response on the part of the fruit to a physical damage. This occurred on several orchards also in the San Luis Obispo area and it seemed to happen in orchards that had recently been sprayed for avocado thrips. No piercing-sucking insects were found at any of these sites. Insects that would feed by feeding on the fruit and causing damage and malformed fruit. Insects that could typically make probing inspections of fruit prior to laying eggs. No eggs or larvae were found in the fruit. Nothing like lygus bug, BMSB, Bagrada bug or other stink bugs was found.
http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=15198
Did it have anything to do with the spray? With the hot weather? With the hot weather and the spray? With the hot weather and the insects that came with it? Did it have anything to do with the hot weather? Did it have anything to do with insects?
And then late June, the calls stopped. No more damaged fruit was being found. And then a lone call from Cayucos. Damage was found on young and older fruit. New damage seemed to be occurring on the fruit that normally sets later in that northern area. The grower walked the orchard and didn't find any bugs. The PCA swept the grove for insects. A yellow sticky card was put out.
So far, no insect has been found on the fruit. So what caused and "is" causing the damage to the fruit? It's not clear. Fruit that was damaged in Oxnard back in late May was tagged to see if it recovered. Ten fruit were flagged and two months later, those tagged fruit were still on the trees. So either the fruit that was attacked fell off with the initial damage or the fruit observed later had healed itself. Fruit have this capacity when they are actively growing to cover over damage. Often it is malformed. In most of cases with this fruit, the damage was very superficial. Occasionally, there deeper pits, but we didn't see any burrowing or tunneling.
If anyone else saw similar damage and has more to offer about this happening, I would be glad to hear about it.
Photos: Damaged fruit that was flagged and observed 2 months later.
- Author: Kathy Keatley Garvey
Oh, if we could just engage in some menu planning and preparation!
How often have you thought of that after watching praying mantids dine on honey bees, bumble bees, monarchs, Western tiger swallowtails and other beneficial insects?
"Please don't eat the pollinators!" I plead, tongue in cheek. "Why not grab a tasty stink bug?"
Well, last Saturday afternoon, Nov. 19 at the Bohart Museum of Entomology, UC Davis, that's exactly what a mantid did. It nailed a stink bug, held it between its spiked forelegs and ate it, not unlike an Thanksgiving-Day interaction between a two-legged human being and a turkey drumstick.
UC Davis entomology graduate student Charlotte Herbert happened by and took a selfie. Serendipity: one of her class assignments was to take a selfie with an insect.
No doubt she was the only one in her class who took a selfie with a praying mantis eating a stink bug!
The occasion: a Bohart open house themed "Uninvited Guests: Common Pests Found in the Home."
The Bohart Museum, home of a global collection of nearly eight million insect specimens (plua a live "petting zoo" and a gift shop) is now gearing up for its next open house, "Parasite Palooza: Botflies, Fleas and Mites, Oh My!" set from 1 to 4 p.m., Sunday, Jan. 22 in Room 1124 of the Academic Surge Building, Crocker Lane. The open houses are free and open to the public. See schedule.
The Bohart Museum's regular hours are from 9 a.m. to noon and 1 to 5 p.m. Mondays through Thursdays. The museum is closed to the public on Fridays, Saturdays and Sundays and on major holidays. Admission is free. More information on the Bohart Museum is available by contacting (530) 752-0493 or bmuseum@ucdavis.edu.