No abstract

The aims of this study were: (a) determine the prey stage preference of female Euseius hibisci (Chant) (Phytoseiidae) at constant densities of different stages of Tetranychus urticae Koch (Tetranychidae), (b) assess the functional response of the predator females to the varying densities of eggs, larvae, or protonymphs of T. urticae, and (c) estimate the functional response of E. hibisci when pollen of Ligustrum ovalifolium was present as well. We conducted experiments on excised pieces of strawberry leaf arenas (Fragaria ananassa) under laboratory conditions of 25+/-2 degrees C, 60+/-5% RH and 12 h photophase. Our results indicated that the predator consumed significantly more prey eggs than other prey stages. Consumption of prey deutonymphs and adults was so low that they were excluded from the non-choice functional response experiments. The functional response on all food items was of type II. The two parameters of the functional response were estimated for each prey type by means of the adjusted non-linear regression model. The highest estimated value a' (instantaneous rate of discovery) and the lowest value of Th (handling time, including digestion) were found for the predator feeding on prey eggs, and a' was lowest and Th highest when fed protonymphs. Using the jack-knife method, the values for the functional response parameters were estimated. The values of a' and Th produced by the model were similar among all prey types except for the eggs, which were different. Using pollen simultaneously with prey larvae decreased the consumption of the latter over the full range of prey densities The suitability of this predator for biological control of T. urticae on strawberry is discussed.

Sensory descriptors of mango 'Ataulfo' treated with dose of γ-rad (Cobalt 60) of 0, 0.15, 0.30, and 0.45 kGys were evaluated. Eight trained panelists evaluated eleven sensory descriptors, three on taste, four on texture and four on odor. Judges found significant differences (P < 0.05) for sweetness, sourness, astringency, juiciness, firmness, mango odor and honey odor in at least one treatment. The principal component analysis revealed a positively association between juiciness, mango odor, and honey odor with the irradiation dose of 0.30 kGy, besides the positively association between creaminess and the irradiation dose of 0.15 kGy. Any descriptors were influenced clearly by the radiation with dose at 0.45 kGy. Dose of 0.15 kGy of radiation can be used as phytosanitary treatment without substantially affecting the sensory properties of mango 'Ataulfo'.

No abstract