Economic thresholds of Thrips palmi (Thysanoptera: Thripidae) for eggplants in a greenhouse
Thrips palmi Karny has recently been implicated in damage to eggplant fruits. This thrips causes cosmetic scars on and deforms fruits, thus lowering their market value. To investigate the relationship between the density of thrips and the resulting damage, experimental plots with initial release densities of 0, 20, 40, 70, and 100 adults thrips per plot were established under greenhouse conditions. Thrips density (for flower sampling = x1; for sticky trap = x2) was monitored using flower sampling and blue sticky trap counts, and was found to be directly related to the proportion of damaged-fruits (y) and the reduction in fruit yield: significant relationships were found for the flower samples (y = 1.2261x1 − 0.6232, r2 = 0.8582) and for the trap catches (y = 11.667 ln(x2) − 9.5, r2 = 0.8896). The proportion of damaged fruits that could be tolerated from an economic perspective, based on the cost of controlling the thrips population chemically and the market value of the fruit, was 6.67–11.76 %; this translated into economic thresholds of 1.05–1.5 adults and/or larvae of T. palmi per flower or 4.91–10.17 adults T. palmi per four-day sticky card count.
Comparative study between biological and chemical control programs of certain sweet pepper pests in greenhouses
Sweet pepper is an important vegetable crop in Egypt. It is cultivated for local consumption and exportation. The crop is attacked by a large number of pest species such as Western flower thrips, Frankliniella occidentalis (Pergande), whitefly, Bemisia tabaci (Genn.), the two-spotted spider mite, Tetranychu surticae Koch, and the beet armyworm, Spodoptera exigua (Hubner). The present study was conducted on the sweet pepper cultivated in greenhouses, during the winter plantation 2016/17 in a commercial farm located at Berkash district, Giza Governorate, Egypt. Three control programs were practiced: the first used biological control agents (BC), the predators, Orius albidipennis (Reuter), Macrolophus caliginosus (Wagner), Chrysoperla carnea (Steph.), and the egg parasitoid, Trichogramma euproctidis (Girault); the second was sprayed by the recommended chemical control program of the farm (CC); and the third was untreated as a control. Obtained results revealed that the BC program was the most significant one for controlling the complex of sweet pepper pests. Also, applying the BC program resulted to a high yield of sweet pepper production (35.06% increasing than the control).
Adsorption of immunoglobulin Y in supermacroporous continuous cryogel with immobilized Cu(2+) ions.
The influence of temperature, pH and ionic strength on the adsorption of Immunoglobulin Y (IgY) in IDA-Cu(2+) cryogel system was studied by batch equilibrium measurements. The adsorptive equilibrium data were obtained at 17 and 27°C, pH 5.0 and 6.5, and at ionic strength of 50 and 200mmolL(-1) NaCl. Langmuir, Freundlich and Langmuir-Freundlich models were fitted to equilibrium data, while the enthalpy of adsorption of IgY in IDA-Cu(2+) cryogel system was calculated through Van't Hoff analysis. The binding of IgY on cryogel was stronger at 27°C and lowest pH and ionic strength values, with apparent maximum adsorption capacity of 27mgg(-1). The adsorption of protein in the resin was spontaneous in all analyzed cases. The results provide valuable information to enable the improvement of IgY purification processes.