Abstract

SIERRA, Paola Vanessa; QUIROGA, Luisa Fernanda  and  VARON, Édgar Herney. Whitefly (Paraleyrodes sp.) preference for avocado cultivars (Persea americana Mill.) in Fresno, Tolima. Corpoica cienc. tecnol. agropecu. [online]. 2014, vol.15, n.2, pp.197-206. ISSN 0122-8706.

The whitefly is a major pest that affects avocado and there is not enough information about the biolog y and management of this insect in Colombia. In this paper the incidence of the whitefly Paraleyrodes sp. pos. bondari on four avocado cultivars was studied (Choquette, Hass, Lorena, Santana). The crop management carried out by farmers was characterized and its effect on the white fly presence on three cultivars was evaluated (Choquette, Hass, Lorena). Presence of secondary metabolites on leaves from Hass and Lorena was measured and the effect of their leaf extracts on the mortality and repellency index of whitefly adults was established. There were interactions between crop management and cultivar for the presence of the insect; moderately chemical management had the lowest infestation in all cultivars. The increase in soil fertilization and chemical insecticides increased insect population, and removal of the hemiparasite decreased it. Lorena cultivar had the highest fly preference, insect population increase when there was interaction between cultivar and mature leaves, neutral repellency index, and high percentage of total and non-reducing carbohydrates. The Hass cultivar showed higher amount of coumarins, terpenes and steroids, and high rate of repellency. Lorena attracting the insect is due to the presence of carbohydrates; and Hass repellency is due to the terpene and / or steroids. Research works should be done on whitefly in avocado crops toward cultivars Lorena.

Keywords : leaf area; extract; infestation; secondary metabolites; repellency.

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