Most of these agents are likely to have dispersed from South Africa, and the rivers of southern Mozambique are likely to be benefitting from the transnational dispersal of these agents. (Azollaceae), and it supported small numbers of the weevil Stenopelmus rufinasus Gyllenhal (Coleoptera: Curculionidae). cristata Kaulfuss (Azollaceae) not the more widely recorded A. Pistia stratiotes supported small numbers of the weevil Neohydronomus affinis Hustache (Coleoptera: Curculionidae). Gams (Hypocreales) and the mite Orthogalumna terebrantis Wallwork (Acarina: Sarcoptiformes: Galumnidae). bruchi Hustache (Coleoptera: Curculionidae) were on water hyacinth, along with the pathogen Acremonium zonatum (Sawada) W. The weevils Neochetina eichhorniae Warner (Coleoptera: Curculionidae) and N. In 2009, we assessed the status of these weeds in seven rivers across southern Mozambique and recorded whether any biocontrol agents were present. (Salviniaceae)) are significant weeds in the south of the country. (Azollaceae)) and salvinia (Salvinia molesta DS Mitch. (Araceae)), red water ferns ( Azolla spp. Release of biological control agents has been limited to Mozambique, where water hyacinth ( Eichhornia crassipes (Mart.) Solms-Laubach (Pontederiaceae)), water lettuce ( Pistia stratiotes L. Extensive studies involving multitrophic interactions should be an essential part of pre-release assessments to enhance the success rates of biological control of weeds.Biological control is an effective ways of controlling aquatic plants, especially in South Africa. This result suggests an initial development of a plant defense response due to mirid feeding delaying the pathogen from establishing. By the 30th day, maximum percentage damage (77.9%) was observed in the treatment of 21 day old fungal culture with 20 mirid density/plant despite of initial delay in disease initiation. zonatum was observed on water hyacinth with 10 and 20 mirids/plant respectively. In treatments involving mirids, the shortest (1.78 days) and the longest (13.22 days) disease initiation time by A. Introduction Insects and plant pathogens have been employed as biocontrol agents against the same weed species. Keywords:defence, induction, insectpathogen synergism, nutrition, plant stress. In absence of mirids, the lowest (3.1 days) and the highest (5.1 days) disease initiation time was observed using 21 and 42 days old culture respectively. crassipes weevils by changing plant biochemical components. zonatum grown for different time durations with different insect densities on water hyacinth. Observations were made on disease initiation time of A. more The possibilities of a positive or negative impact the biocontrol agents may have on each other as well as on the control of the weed itself, inspired us to study the interactions between the mirid, Eccritotarsus catarinensis and the phytopathogen, Acremonium zonatum, biocontrol agents of water hyacinth, Eichhornia crassipes. The possibilities of a positive or negative impact the biocontrol agents may have on each other a. eich-horniae (87.6 and 65.8%) for W+ and W− waterhya. By 45 d after treatment, DI was sig-nificantly higher in F. A disease index (DI) of damaged plants varied significantly with different pathogens. The W+ plants were more prone to fungal infection as compared to W− waterhyacinth. Cole-optera: Curculionidae treatment W+) and on plants with no insect feeding damage (W−). They were applied to waterhyacinth in two treatments: on plants with feeding scars of weevils (Neochetina sp. solani Sacc., and Myrothecium roridum Tode ex Fr) were test-ed for their disease-causing potential against waterhyacinth (Eichhornia crassipes Solms-Laubach Pontederiace-ae). alternata Keissler, Acremonium zona-tum Gams, Fusarium oxysporum Schlecht, F. During this study, six South African fungal isolates (Alternaria eichhorniae Nagraj and Ponappa, A. more Feeding damage by arthropods is known to render water-hyacinth plants vulnerable to diseases. Feeding damage by arthropods is known to render water-hyacinth plants vulnerable to diseases.