ARS Grant Recipient Culin Addresses William Bartram Chapter
Bobby D. Barnett
Clemson, South Carolina
Dr. Joe Culin, recipient of an ARS research grant, addressed the William Bartram Chapter on October 10 in Greenville, SC. Dr. Culin is assistant professor of Entomology at Clemson University, Clemson, South Carolina. His research project funded at $1500 is to investigate the biology, control and host-pest relationship of the rhododendron tip borer.
Boris Bauer (left), President of the William Bartram Chapter,
congratulates Clemson University Professor Joe Culin on
receipt of an ARS research grant for work on the biology and
the control of the rhododendron tip borer.
Photo by Bobby D. Barnett
Dr. Culin outlined his research proposal, and asked for ARS member assistance in identifying more susceptible varieties and in obtaining infested plant material. Dr. Culin reported that a portion of the $1500 grant will be used for constructing a screened enclosure. This will confine the pests he will allow to reproduce to the experimental area, thus protecting local fanciers and the Clemson University Horticulture Gardens from a build-up of the borer.
Dr. Culin discussed the clear-wing moth as a pest that may be confused with the tip borer. He reported that a series of papers from the USDA lab in Washington, D.C. has brought our knowledge of the moth to an advanced level as compared to what we know about the borer. He explained that the caterpillar from which the moth emerges does its damage nearer the surface of the stem while the borer grub tunnels through the very center of the stem it attacks. Also, the borer initially damages new growth, hence the name tip borer, while the moth enters near the base of the plant. The borer that attacks rhododendrons is similar to a borer that attacks blueberries and another that infests dogwoods. In fact, it is possible, he said, that they may be the same borer. Because of the economic value of the blueberry, more work has been done with the borer's damage to that species.
Dr. Culin observed that ornamental plants that are grown near the limits of their geographic habitat boundaries or in local sites that are inhospitable are often subject to higher levels of infestation. He hopes to determine what environmental factors may predispose rhododendrons to the borer in his proposed work.
Dr. Culin noted that control of the borer is primarily done now by pruning stems that wilt and by destroying that portion of the plant that contains the grub. The method of entry into the plant, the length of time from egg laying to maturity of the resulting beetle and effective pesticides are all unknown at present. Dr. Culin expressed the hope that he could report to the Society on answers to some of these questions at a future date.