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|Title:||Efficacy of Sameodes albiguttalis as a biocontrol of waterhyacinth|
|Authors:||United States. Science and Education Administration.|
Aquatic Plant Control Research Program (U.S.)
Center, Ted D.
Durden, Willey C.
Corman, Debra A.
|Keywords:||Aquatic plant control|
|Publisher:||Environmental Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
Abstract: Sameodes albiguttalis (Warren) is a South American pyralid moth species which was released in Florida in 1977 for the biological control of waterhyacinth. After it was determined that populations of this insect had become established in the field, various efficacy studies were begun. The first of these began in September 1978 and, ultimately, data were collected at 15 sites from throughout Florida. The objectives of these studies were to determine (A.) if s. albiguttalis would be persistent, (B.) if it could be augmented if it were not persistent, and (C.) if it had a significant impact upon waterhyacinth populations within the context of comparisons among other control agents and the plant's ability to recover from serious njury. Data indicate that S. albiguttalis will, under certain conditions, be an effective biological control of waterhyacinth. This will generally be true only where the waterhyacinth population is in a predominantly colonizing mode. In these situations the plants are small, luxuriantly growing, have large, inflated leaf petioles, and often do not exist as part of a continuous mat. Infestations are usually heaviest along the developing fringe of a mat or in areas where the plants have been killed by frost, drought, or herbicide and are regrowing. Life table studies of waterhyacinth leaves show distinct spatial patterns. Only S. albiguttalis larvae, weevil adults, weevil larvae, and occasionally environmental factors affect the young leaves, injure the apical buds of the shoots, cause leaf production to cease, and effectively kill the shoots. Most other factors usually only cause superficial injury and usually only to older leaves, although sporadic outbreaks of any of these agents may temporarily cause severe shoot injury. It is estimated that biological control by S. albiguttalis and the two species of waterhyacinth weevil results in an overall 34% reduction in waterhyacinth productivity. This is based upon the observed reduction to leaf longevity which is usually brought about by the early destruction of young leaves. Unfortunately, damage caused by S. albiguttalis larvae is sporadic. Sameodes albiguttalis, more than either of the other two waterhyacinth insects (Neochetina eichhorniae and N. bruchi), should fit comfortably into a management scheme . Its effectiveness may be maximized in a maintenance program where the waterhyacinth population is constantly perturbed and is always in a colonizing mode. Many possible management strategies exist in which this insect and herbicidal or mechanical control could be integrated and experimentation along these lines should be given a high future priority. NOTE: This file is very large. Allow your browser 3-5 minutes to download the file.
|Appears in Collections:||Technical Report|