Biological Control with Insects: The Alligatorweed Stem-borer

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Title:
Biological Control with Insects: The Alligatorweed Stem-borer
Physical Description:
Fact sheet
Creator:
Center, Ted D.
Publisher:
University of Florida Cooperative Extension Service, Institute of Food and Agriculture Sciences, EDIS
Place of Publication:
Gainesville, Fla.
Publication Date:

Notes

Acquisition:
Collected for University of Florida's Institutional Repository by the UFIR Self-Submittal tool. Submitted by Melanie Mercer.
Publication Status:
Published
General Note:
"Revised: May 2002."
General Note:
"SS AGR 134"

Record Information

Source Institution:
University of Florida Institutional Repository
Holding Location:
University of Florida
Rights Management:
All rights reserved by the submitter.
System ID:
IR00004563:00001


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SS-AGR-134 Biological Control with Insects: The Alligatorweed Stem-borer 1 Ted D. Center, F. Allen Dray, and Vernon V. Vandiver, Jr.2 1. This document is SS AGR 134, one of a series of the Department of Agronomy, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Revised: May 2002. Please visit the EDIS Web site at http://edis.ifas.ufl.edu. 2. Ted D. Center, Research Entomologist, USDA Agricultural Research Service, Invasive Plant Research Laboratory, Fort Lauderdale, FL 33314; F. Allen Dray, Ecologist, USDA Agricultural Research Service, Invasive Plant Research Laboratory, Fort Lauderdale, FL 33314; and Vernon V. Vandiver, Associate Professor and Extension Aquatic Weeds Specialist, Fort Lauderdale Research and Education Center, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611. The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin. For information on obtaining other extension publications, contact your county Cooperative Extension Service office. Florida Cooperative Extension Service/Institute of Food and Agricultural Sciences/University of Florida/Christine Taylor Waddill, Dean. ( Vogtia malloi Pastrana Lepidoptera: Pyralidae: Phycitinae) Host : Alternanthera philoxeroides (Mart.) Griseb. (Amaranthaceae) Dr. George Vogt explored extensively for biological control agents of alligatorweed during 1960 to 1962, particularly in northern Argentina, southern Brazil and Paraguay. One of the most widespread species that he encountered was an undescribed moth, the genus of which was later named in his honor, Vogtia malloi It occurred from tropical Guyana through tropical Brazil to temperate Argentina, and appeared to be a potentially effective biological control agent. After further study, approval for its release in the U.S. was granted in 1970. Releases were made during 1971 in southern Georgia and northern Florida and its effectiveness was apparent by 1972. Unlike the alligatorweed flea beetle, V. malloi appears capable of overwintering in northern areas. The adult female deposits oval eggs (0.7 mm by 0.44 mm) singly on the undersides of young leaves near the leaf margin or in the midvein or in the leaf axil. The egg is white at first but becomes yellow as the embryo develops. It hatches in about 6 days. The larvae go through five instars over a period of about 24 days (at 23C). First instars immediately tunnel into the host plant through the 1st to 4th internodes of the apical stem portion. Older larvae may enter stems at a lower level and burrow upwards devouring wall tissue nearly to the epidermis. A single larva may destroy five to nine stems during the course of its development. The damage creates a distinctive tip-wilt that easily characterizes an infested mat. Pupation occurs within the stem in a sealed chamber created by the larva. The pupa is formed within a silken cocoon in a cavity in the stem. Prior to pupation the larva bites a circular hole (2 mm diameter) through the stem wall but not through the outer epidermis. The adult moth emerges by rupturing the thin membranous epidermis covering the hole previously created by the larva. The adult is nocturnal. During the day it is quiescent and rests in an angled position, supporting itself with the four hind legs. Females lay

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Biological Control with Insects: The Alligatorweed Stem-borer 2 an average of 267 eggs over a 6 to 8 day period. Females live 6 to 10 days and males 5 to 9 days. The damage caused by V. malloi compliments that of A. hygrophila. Alligatorweed mats may recover from attack by one of these agents, but not from attack of both. Stems normally remain erect after defoliating attacks of the flea beetle but the burrowing of Vogtia larvae causes them to collapse giving the mat a flattened appearance. Much of the credit given to the flea beetle for alligatorweed control probably rightly belongs to V. malloi.