Population Dynamics of Waterhyacinth and the Biological Control Agent Neochetina eichhorniae (Coleoptera: Curculionidae) at a Southeast Texas Location

1991 ◽  
Vol 20 (2) ◽  
pp. 652-660 ◽  
Author(s):  
Michael J. Grodowitz ◽  
Robert Michael Stewart ◽  
Alfred F. Cofrancesco
Keyword(s):  
Biological Control ◽  
Population Dynamics ◽  
Biological Control Agent ◽  
Control Agent ◽  
Neochetina Eichhorniae ◽  
Southeast Texas

The pathogenicity of an Australian isolate of Acremonium zonatum to water hyacinth, and its relationship with the biological control agent, Neochetina eichhorniae

1987 ◽  
Vol 38 (1) ◽  
pp. 219 ◽  
Author(s):  
JC Galbraith
Keyword(s):  
Biological Control ◽  
Water Hyacinth ◽  
Biological Control Agent ◽  
Control Agent ◽  
Control Programme ◽  
Australian Isolate ◽  
Free Moisture ◽  
Neochetina Eichhorniae ◽  
Dry Conditions ◽  
The Individual

The first description of Acremonium zonatum on water hyacinth in Australia is made. Its pathogenicity was studied as part of the search for a microorganism already present in Australia which could be developed as a mychoherbicide to supplement the arthropod biological control programme in this country. Following inoculation with A. zonatum, extensive leaf infections developed, favoured by injury and free moisture, but new leaves continued to form. Feeding by the weevil, Neochetina eichhorniae, increased infection by A. zonatum in relatively dry conditions, but it is unlikely that this was due to feeding scars acting as ports of entry. A. zonatum spores were transported on the feet and in the digestive tract of the weevil. The growth of infected plants, estimated by standing crop, was reduced by 49% compared to the control. A further decrease occurred in infected plants infested by weevils, but the total reduction in growth was not equal to the sum of the individual effects of fungus and weevil. Infection did not develop in 15 other plant species inoculated with the Australian isolate of A. zonatum. Although not a virulent pathogen, A. zonatum has some favourable characteristics for consideration as a mycoherbicide and has not appeared antagonistic to N. eichhorniae in these studies. Its role probably lies in exerting a chronic stress on plants already under attack by arthropod biological control agents.

A process-based population dynamics model to explore target and non-target impacts of a biological control agent

2009 ◽  
Vol 220 (17) ◽  
pp. 2035-2050 ◽  
Author(s):  
Darren J. Kriticos ◽  
Michael S. Watt ◽  
Toni M. Withers ◽  
Agathe Leriche ◽  
Michelle C. Watson
Keyword(s):  
Biological Control ◽  
Population Dynamics ◽  
Biological Control Agent ◽  
Control Agent ◽  
Dynamics Model ◽  
Population Dynamics Model

Population Dynamics of Broadleaf Weeds in Turfgrass as Influenced by Chemical and Biological Control Methods

Weed Science ◽  
2007 ◽  
Vol 55 (4) ◽  
pp. 371-380 ◽  
Author(s):  
Mohammed H. Abu-Dieyeh ◽  
Alan K. Watson
Keyword(s):  
Biological Control ◽  
Population Dynamics ◽  
Weed Control ◽  
Seed Bank ◽  
Biological Control Agent ◽  
Control Agent ◽  
Weed Species ◽  
Early Autumn ◽  
Herbicide Treatment ◽  
Broadleaf Species

A 3-yr field study was conducted to determine the effect of a biological control agent,Sclerotinia minorJagger, and a common herbicide, Killex, on the population dynamics of dandelion and other broadleaf species and on the dandelion seed bank. Treatments were applied as one spring, one early autumn, or a spring plus an early autumn treatment per year. The response of the dandelion population to a spring herbicide treatment was similar to two applications per year (spring and early autumn). Significantly less dandelion control occurred after the first early autumn application of the herbicide. Two weeks after application, spring or early autumn treatments withS. minorwere equally effective in suppressing dandelions. In the second year of the two applications per year ofS. minortreatment, weed control was equivalent to the herbicide. By the third year of the one spring application ofS. minor, weed control was equivalent to the herbicide. Generally over the study period, the early autumn application ofS. minorwas less effective than the spring or the spring and early autumn applications. TheS. minortreatments significantly reduced the dandelion seed bank, and this effect was not significantly different from the Killex herbicide treatment. The rate, frequency, and seasonal timing of application had no effect on the dandelion seed-bank size, but terminating the application would gradually replenish the seed bank. Populations of white clover, broadleaf plantain, birdsfoot trefoil, and common ragweed were similarly suppressed by either theS. minoror the herbicide treatments. Yellow woodsorrel significantly increased after 1 yr of herbicide treatment compared with theS. minorand untreated control treatments, indicating a possible weed species shift. Turf quality was improved because of the herbicide andS. minortreatments, but grass injury and smooth crabgrass invasion were recorded in 17% of herbicide-treated plots.

scholarly journals Chevroned Water Hyacinth weevil Neochetina bruchi Hustache (Insecta: Coleoptera: Curculionidae)

EDIS ◽  
2021 ◽  
Vol 2021 (2) ◽  
pp. 6
Author(s):  
Eutychus Kariuki ◽  
Carey Minteer
Keyword(s):  
United States ◽  
Biological Control ◽  
Water Hyacinth ◽  
Gulf Coast ◽  
Biological Control Agent ◽  
The United States ◽  
Control Agent ◽  
Weed Biological Control ◽  
Invasive Aquatic Plant ◽  
Neochetina Eichhorniae

Neochetina bruchi Hustache is commonly referred to as the chevroned water hyacinth weevil and is a weed biological control agent used to manage water hyacinth, Pontederia crassipes Mart. [formely Eichhornia crassipes (Mart.) Solms (Pellegrini et al. 2018)], in more than 30 countries (Winston et al. 2014). Imported from Argentina, the insect was first introduced into the United States in Florida in 1974 and released in Louisiana later in 1974 (Manning 1979), Texas 1980, and California 1982 to 1983 (Winston et al. 2014). Now Neochetina bruchi occurs throughout the Gulf Coast States (Winston et al. 2014). The target weed of Neochetina bruchi, water hyacinth, is an invasive aquatic plant in the United States and is included on Florida’s list of prohibited aquatic plants. Neochetina bruchi is among four species of insect biological control agents that have been introduced into the United States to manage water hyacinth. The other three species include a weevil, Neochetina eichhorniae; a moth, Niphograptaalbiguttalis; and a planthopper, Megamelus scutellaris, which were introduced into the United States in 1972, 1977, and 2010, respectively (Tipping et al. 2014). Although the larvae and pupae of Neochetina bruchi and Neochetina eichhorniae have similar appearance and behavior and can be difficult to differentiate by casual observation (Deloach and Cordo 1976), the adult stages of the two species of water hyacinth weevils can be distinguished relatively easily based on the color patterns on their elytra (hardened fore wings).

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