IPM Voice Newsletter                                     June 2016
In This Issue: New Study Quantifies High Costs of Imported Forest Pests; Scientists Use Peach Pit Chemistry to Develop Protective Seed Coating; New Experimental Device Uses Sound to Disrupt Citrus Psyllid's Mating
New Study Quantifies High Costs of Imported Forest Pests

Imported tree pests have decimated eastern chestnuts and elms in the U.S., and currently more than 400 species of invasive forest pests are attacking hemlock, ash, beech, oak, maple and dogwood. Every state is affected, and a team of scientists has estimated that the number of introduced wood-boring insects could triple by 2050 if policies do not shift..
 
The team of sixteen scientists estimates that forest pests cause $2 billion in damage annually, with homeowners and municipalities bearing the brunt of the cost to remove and replant trees that take decades to grow back to full size. Their study, published in Ecological Applications, provides the most comprehensive analysis of the issue to date and includes representation from Harvard Forest, the USDA Forest Service, The Nature Conservancy, Dartmouth College, McGill University, and Michigan State. The team was convened by the consortium The Science Policy Exchange.
 
Invasive forest pests and diseases are the only threat to forests that have the potential to wipe out entire species of trees. The loss of trees in urban and suburban areas degrades multiple ecosystem services and affects property values, cooling, flooding, air quality and aesthetics.
 
To solve this pressing issue, the scientists advocate for changes in trade policies to block the routes by which forest pests are entering, with an ultimate goal of shifting the costs back to the suppliers and importers who are ultimately responsible for pest introductions.  Recommendations include eliminating solid wood shipping pallets and switching to non-solid wood packaging, ending or greatly limiting imports of live woody plants, expanding early detection and rapid response programs, augmenting international pest prevention programs with key trade partners and increasing penalties for non-compliant shippers and importers.
 
Wooden pallets are often cited as one of the worst vehicles for introduction of invasive pests.  Alternatives include "engineered wood," made with a product similar to corrugated cardboard or a heat and glue laminating process, or plastic pallets.
 
Woody plants are equally important vehicles for entry. Seventy percent of invasive forest pests have arrived on our continent via imported plants. Some nursery retailers are already onboard with this policy.
 
Enforcement is also key. Under current regulations, shippers and importers may violate wood packaging treatment requirements five times before facing a penalty. Frank Lowenstein, deputy director of the New England Forestry Foundation, acknowledges that there will likely be resistance to these policy changes from overseas shipping partners, but "moving away from solid wood packaging could be really beneficial ecologically not only here in the United States but in some of our international trading partners' forests as well." He cites how Indonesian old-growth hardwood forests that provide orangutan habitat have been harvested to provide wood for shipping pallets for Chinese exports.
 
For more, read the study here or visit Phys.org for a series of articles on the study.
Scientists Use Peach Pit Chemistry to Develop Protective Seed Coating

Chemists from a research group in Zurich have hit upon a novel method to protect seeds from seed-feeding insect larvae by using a natural defense employed by peaches, apricots and bitter almonds. Amygdalin is a substance found in peach pits, apricot pits and the skin of the bitter almond. Researchers from ETH Zurich have incorporated amygdalin into an effective protective coating for seeds that does not impair seed germination and is biodegradable. Scientists are hopeful this new method could replace certain synthetic seed coatings.
 
The seed coating consists of several layers of polylactic acid (PLA), a substance harmless to humans and the environment, two layers of amygdalin, and an enzyme layer that interacts with the amygdalin when it's breached by a feeding insect larva. As larvae feed on treated seeds, the enzyme and the amygdalin break down into hydrogen cyanide in the insect gut and kill the larva. In trials, fewer full-grown beetles were found to hatch on coated seeds, reproduction was hampered and larvae grew more slowly because they had less food available. The method has been tested on several persistent pests and found to be effective against larvae of mealworms (Tenebrio molitor), Indian mealmoths (Plodia interpunctella) and lesser grain borers (Rhizopertha dominica), but not wheat weevils, (Sitophilus granaries) an insect that bores into seeds and lays eggs that hatch from inside out.
 
In the laboratory, 98% of coated seeds germinated; in the field, seeds germinated slightly later but were able to recover overall. The method is projected to be no more expensive than current conventional synthetic seed coatings. For more, read the study at the Journal of Agricultural and Food Chemistry or see the article at Futurity.
New Experimental Device Uses Sound to Disrupt Citrus Psyllid's Mating

Scientists from the Agricultural Research Service have developed a new mating disruption device to combat the Asian citrus psyllid. This psyllid is an invasive pest responsible for the spread of the bacterium that causes Huánglóngběng, also known as citrus greening disease. Trees infected with citrus greening produce misshapen, acidic, inedible, unsalable fruit and eventually die. The disease is currently incurable. Researchers have been scrambling for solutions, particularly in the face of rising insecticide use to combat the psyllids.
 
The new device mimics wing vibrations produced by male and female citrus psyllids to attract each other. Most mating-disruption techniques are pheromone-based, but the developers of the new device, entomologist Richard Mankin and his University of Florida graduate team, decoded the psyllid's acoustic mating signals and were able to reproduce them using electronics.
 
In the wild, male psyllids beat their wings in a precise pattern, sending vibrations along branches and foliage. Receptive females will respond with a buzz of their own approximately half a second later. In the lab, Mankin and his team were able to respond to the male buzz with the acoustic device's electronic response only one tenth of a second later, effectively luring the males towards a sticky trap. In the presence of the devices, male psyllids were found to be four times less likely to locate females than they were in control groups.

The acoustic trap is still in development. Mankin and his team hope to reduce its cost to $50 and perfect its workings in order to bring it to the market commercially as soon as possible. Read more about the trap and the efforts to combat Huánglóngběng at the USDA ARS Online Magazine.
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Upcoming IPM-Related Meetings and Conferences
University Park, PA
September 25-30, 2016. XXV International Congress of Entomology. Orlando, FL
October 4-6, 2016. National Forum on Climate and Pests. Washington, D.C. & Online 

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