On Thursday, Sept. 6, Carol Bullard, MSPB Administrator, sent me an email about her conversation with Mr. Michael Ledlow, Miss. Bureau of Plant Industry Director, regarding the Guava root knot nematode (RKN). Since I had not seen (or rather passed over) a recent article in Delta Farm Press by Brad Robb (July 27, 2018) about this new pest found in Louisiana, I realized I should find out just what is known about this pest and its potential to infest Mississippi soybeans.
The first article that I am aware of about this pest’s occurrence in the Midsouth is one by Dr. Charles Overstreet (LSU Professor in the Plant Pathology and Crop Physiology Dept.) titled “The Guava root-knot nematode–A new pest in Louisiana”. Dr. Overstreet emphasizes the following points about the Guava RKN pest.
• The Guava RKN is considered one of the most damaging nematodes in the world because of its wide host range, aggressiveness, and ability to overcome current RKN resistance in crops.
• Presently, it is thought to have very limited distribution in Louisiana, occurring at only one location.
• Since it is likely that this nematode will spread, producers should be aware of what to look for.
• The Guava RKN is very similar to the common Southern RKN that is pervasive in the Midsouth (and increasing in prominence as per my conversations with Miss. pathologists).
• Distinguishing between Guava and Southern RKN’s can be difficult because both can produce rather large root galls.
• Its presence can be recognized when plants that are resistant to Southern RKN have large galls on their roots and suffer serious damage.
• The isolate found in Louisiana is particularly damaging to sweet potato and tomato, but soybean, cotton, and peanut are also susceptible to this pest.
• The best defense against this potential nematode pest is to prevent its incursion into uninfested fields where susceptible crops are/will be grown.
Public agency and regional commodity group administrators are aware of this new pest and its potential to infest Midsouth soybeans. Hopefully, their support for a proactive vs. reactive approach will lead to increased knowledge about this pest and the development of potential remedies that can be used if/when it invades upper portions of the Midsouth.
The intent of this article is not to convey a doomsday scenario, but rather to make producers, consultants, and other agricultural practitioners aware of this new invasive pest so that they can be involved in its detection and use/evaluation of possible remedies should they be necessary.
Composed by Larry G. Heatherly, Sept. 2018, firstname.lastname@example.org