Infestation

About: Infestation is a research topic. Over the lifetime, 8308 publications have been published within this topic receiving 82305 citations.

Effect of potato used as a trap crop on potato cyst nematodes and other soil pathogens and on the growth of a subsequent main potato crop

Abstract: A field experiment in which main-crop potatoes were grown every other year was conducted on a sandy soil from 1994 to 1999. The aim of the experiment was to control soil-borne pathogens of potato with ecologically sound methods. Potato grown as a trap crop from the end of April to the end of June (8 wk) was used to control potato cyst nematodes (PCN) (Globodera pallida), and its effects on other important soil pathogens and on the growth of a subsequent potato crop were also assessed. Additional experimental treatments were a potato crop from which the haulm was removed and a green manure crop. Three potato cultivars with different degrees of resistance to PCN were grown as the main crop. Duplicate sets of the experiment were run concurrently. The PCN were effectively controlled by the potato trap crop. When a highly resistant potato cultivar was grown as a main crop after the trap crop, the post-harvest soil infestation was very low. When a moderately resistant cultivar was grown after the trap crop the soil infestation also remained low. When the trap crop was alternated with a susceptible potato cultivar as a main crop, soil infestation increased slightly, but the degree of control when compared with no trap crop averaged 96%. Soil infestation with root-knot nematodes (mainly Meloidogyne hapla) increased when potato was grown as a trap crop, but soil infestation with the root-lesion nematode Pratylenchus crenatus was not affected. Stem canker caused by Rhizoctonia solani was not affected by the trap crop but black scurf (sclerotia of R. solani) on tubers was reduced. Soil infestation with Verticillium dahliae declined in one of the duplicate sets of the experiment but not in the other. However, stem infections by V. dahliae were significantly decreased in both sets, although the effect depended on the PCN-resistance level of the potato cultivar. When a highly resistant potato cultivar was grown Verticillium stem infections were not significantly affected, they were decreased with a moderately resistant cultivar but the decrease was most pronounced with a PCN-susceptible cultivar. Senescence of a following potato crop was not influenced by the trap crop when a highly PCN- resistant cultivar was grown, but it was delayed in the case of a moderately resistant or a susceptible cultivar, resulting in higher tuber yields for those cultivars. The experiment proved that a trap crop can be an alternative to chemical soil disinfection but, for several reasons, the potato itself is not an ideal crop for this purpose; a trap crop other than potato must be developed.

Reproductive phenology and pre‐dispersal seed‐feeding in Protium tovarense (Burseraceae), with a description of the first known phytophagous “Bracon” species (Hymenoptera: Braconidae: Braconinae)

Abstract: The reproductive phenology of the cloud forest tree Protium tovarense (Burseraceae) is analysed for one population in northern Venezuela. Reproductive phenophases were monitored using both long‐term(21 years) and detailed short‐term (4 years) surveys of flower and fruit set. The reproductive phenology of this tree varies, with periods in which the species behaves as a supra‐annual reproducer, and other periods in which it reproduces annually, at the end of the rainy season. Marked spatial variation in reproductive condition was also observed, with subpopulations separated by less than 2 km showing contrasting phenological stages. Larval infestation of seeds by a braconid wasp was observed for a period of 1 year and is described. This wasp, the first obligately phytophagous species of Braconinae, is described as Bracon phytophagus Quicke sp. n. Percentage fruit infestation by this wasp was relatively high (50–60%) during the entire period (∼10 months) of fruit development. The larval stages are described a...

Species composition and host range of fruit-infesting flies (Diptera: Tephritidae) in northern Ghana

Abstract: An important aspect of fruit fly management is accurate information on the species and their host spectrum. Studies were conducted between October 2011 and September 2013 to determine the host range and species diversity of pest fruit flies in the northern savannah ecology of Ghana. Fruit samples from 80 potential host plants (wild and cultivated) were collected and incubated for fly emergence; 65 (81.5%) of the plant species were positive to fruit flies. From records in Africa, 11 plant species were reported to be new hosts to the African invader fly, Bactrocera invadens (Drew, Tsuruta and White, 2005). This study documented the first records of Dacus ciliatus (Loew) and Trirhithrum nigerrimum (Bezzi) in northern Ghana although both species have been previously reported in other parts of the country. Infestation by B. invadens was higher in the cultivated fruits; Ceratitis cosyra dominated in most wild fruits. Cucurbitaceae were mainly infested by three species of Dacus and Bactrocera cucurbitae, a specialized cucurbit feeder. Among the commercial fruit species, the highest infestations were observed in mango, tomato, sweet pepper and watermelon, whereas marula plum, soursop, tropical almond, sycamore fig, African peach, shea nut, persimmon, icacina and albarillo dominated the wild host flora. The widespread availability of host plants and the incidence of diverse fly species in the ecology call for particular attention to their impact on commercial fruits and the development of sustainable management strategies against these economically important pests in Ghana.

Effects of scaley-leg mite infestations on body condition and site fidelity of migratory warblers in the dominican republic

Abstract: Rates of infestation by the scaley leg mite (Knemidokoptes jamaicensis) were examined on two overwintering Nearctic-Neotropical migrants, Palm Warbler (Dendroica palmarum) and Prairie Warbler (D. discolor), in low-elevation desert thorn scrub and high-elevation pine forest in the Dominican Republic. Ectoparasites were common on birds in the dry thorn scrub where birds roosted communally, but were never found on birds in the moister pine forest where communal roosting was not detected. Prevalence of ectoparasites varied between years and generally increased in prevalence within winters, with mean rates of infestation reaching as high as 25% among Palm Warblers in late-winter. Parasitized Palm Warblers showed significant decreases in mean pectoral muscle mass scores indicating a negative effect on body condition and physiological stress. Infestation had a significant effect on overwinter site persistence and annual return rates; no infected individuals ever returned the following year. Results of a...