Introduction to scouting in chestnuts
There are many valuable integrated pest management (IPM) resources and tools available to chestnut producers through Michigan State University (MSU). As chestnut production become more heavily reliant on real-time information and addresses evolving issues such as potential invasive pests, rising pesticide costs and challenging environmental conditions, MSU Extension is here to assist chestnut producers in maintaining an IPM program that supports economic and environmental sustainability.
As a relatively new industry, the chestnut industry faces a number of challenges, including the development and implementation of standard scouting practices that detect, identify and properly manage for insect and disease pests. This is not a small challenge and protocols will continue to evolve over time as the industry and University learn more about this ever-changing system. Michigan has a long history of horticultural crop production we can draw from the pest management experiences of industries like apple and cherry to develop some basic scouting techniques for chestnut producers.
Growers should be scouting at least weekly during the growing season, noting growth stages, significant weather events, beneficial insects, pest hot spots or any other useful observations in an easily accessible location that they can refer back to in coming years. Growers can start their scouting program with basic visual inspection. To complete a visual inspection, walk a diagonal transect across each contiguous block stopping to inspect the leaves on 10 branches for insects (potato leafhopper, mites, foliar feeders), phytotoxicity, or abnormalities. Growers may require a hand lens or magnifying glass to view mites as they are small and difficult to see with the naked eye at low populations. Growers may also place unbaited, yellow sticky traps at 4 locations per 5 acre block (two in the interior and two in edge rows). Check and clean/replace these traps as needed weekly.
As growers walk the transect they should take the time to inspect the canopy of the trees for rose chafer and Japanese beetle. Also look for signs of stress or wilt that can be caused by root rot fungi. Growers should also visually inspect the trunks as they walk a transect looking for signs of chestnut blight and sunscald (or southwest disease) which are often confused as they cause similar symptoms. Lastly, growers should be on the lookout for signs of Asian chestnut gall wasp (ACGW), a potential invasive insect of concern that has not yet been found in Michigan. ACGW is easiest to scout for in the fall or winter after the leaves abscise from the tree but can also be seen during the summer.
When it comes to keeping up with the latest developments that affect chestnut production, MSU Extension is an excellent resource. MSU Extension News for agriculture offers the expertise of MSU scientists and educators through online articles addressing pest management in chestnut and providing weekly scouting reports during the growing season. Can’t remember to access the page? That’s okay! You can sign up to receive chestnut related articles via MSUE News sent out each week by email. You can also opt into other topics or cropping systems of interest to you. To subscribe simply click the ‘Sign up for MSUE News’ icon found throughout the MSUE website. Lastly, MSU also offers a number of additional online resources including the IPM webpage, which is devoted to the dissemination of information regarding sustainable pest management practices. For more pest specific information visit the insect and disease sections of this page.