The tomato leafminer, Tuta absoluta, is considered the most devastating tomato pest in Egypt. It has been reported in Egypt since 2009, quickly becoming one of the major pests of the tomato crop. The damage is produced when the larvae feed on the leaf mesophyll expanding mines, thus affecting the photosynthetic capacity of the crop and reducing its yield.
Scientists at the South Valley University have determined the efficacy of five pesticides namely, indoxacarb, abamectin+ thiamethoxam, emamectin benzoate, fipronil and imidacloprid against the 3rd larval instar of T. absoluta under laboratory conditions using the leaf-dip method.
"Results showed that emamectin benzoate was the most toxic compound against the pest, whereas imidacloprid resulted the least toxic one", the scientists say.
According to a decreasing efficacy order, the tested pesticides could be arranged as follows: emamectin benzoate, fipronil, abamectin + thiamethoxam, indoxacarb and imidacloprid. The corresponding LC50 values after 72 hours were 0.07, 0.22, 0.28, 0.59 and 2.67 ppm, while LC90 values were 0.56, 3.25, 1.99, 4.69 and 30.29 ppm, respectively.
"Our study proved that emamectin benzoate can be used as a good compound in integrated management program to control this pest", the scientists conclude.
Source: Mohanny K.M., Mohamed G.S, Allam R.O.H., Ahmed R.A., 'Evaluation of some pesticides against the tomato borer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) under laboratory conditions', 2020, SVU-International Journal of Agricultural Science, Vol. 2, Issue (1), pages 13-20.