Accession Number : ADA085875


Title :   Exploration for Natural Enemies of Hydrilla verticillata in Eastern Africa.


Descriptive Note : Final rept.,


Corporate Author : AGRICULTURAL RESEARCH SERVICE GAINESVILLE FL


Personal Author(s) : Pemberton, Robert W


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a085875.pdf


Report Date : May 1980


Pagination or Media Count : 57


Abstract : This survey of East African water habitats was conducted to find natural enemies of Hydrilla verticillata Royle (Hydrocharitaceae). Since 1960, when it was first recorded, hydrilla has spread through the southeastern part of the United States and has the potential to occupy large portions of freshwater bodies. It not only precludes use of an infested waterway by man but can be ecologically disruptive. A two-phase survey was conducted during September-December 1976--a wide survey through Tanzania and Kenya, followed by an intense survey of Lake Tanganyika, including a preliminary study of hydrilla natural enemies at Kigoma. The noted damage to hydrilla plants was of two types, fish and insect feedings. Fish damage, possibly caused by a chiclid, was in the form of either leaf removal along the stem or the removal of the stem tips. The potentially most important insect found feeding on hydrilla was a Chironomid midge of the genus Polypedilum (species not yet determined). Damage caused by the larvae of this midge was primarily a loss of the apical meristems of the hydrilla shoots resulting in a pruning effect on hydrilla. Recommendations include: (a) Study and evaluate the known natural enemies of hydrilla, Polypedilum sp., fish, mayfly, and caddis fly, to determine their ability to damage hydrilla; and (b) Conduct additional surveys in East Africa to observe hydrilla populations not affected by the meristem borer and to find other natural enemies of hydrilla.


Descriptors :   *BIOLOGICAL WEED CONTROL , *AQUATIC WEEDS , DAMAGE , LAKES , FISHES , KENYA , AQUATIC INSECTS , TANZANIA


Subject Categories : Hygiene and Sanitation
      Agricultural Chemistry


Distribution Statement : APPROVED FOR PUBLIC RELEASE