Abstract
The toxicity of oxamyl against the date palm mite, Oligonychus afrasiaticus (McGregor) was evaluated. This includes the potential of Injo200 and Huwa-San TR50 in increasing the effectiveness of oxamyl against all developmental stages including eggs of O. afrasiaticus. Oxamyl was found to be very effective in controlling the adult of O. afrasiaticus with a little effect on its eggs under laboratory conditions. The mortality percentages of O. afrasiaticus were 61.79, 73.58 and 82.90%; 62.87, 73.77 and 83.32%; 71.70, 82.23 and 92.37% after one week of exposure to the quarter recommended dose (QRD), half recommended dose (HRD) and recommended dose (RD) of oxamyl only and with the recommended dose (RD) of Injo200 or 1000ppm of Huwa-San TR50, respectively. The percentages of larvae hatching from eggs of O. afrasiaticus were 97.20, 94.62 and 85.53%; 94.70, 93.32 and 84.86%; 54.01, 57.93 and 46.21% after one week of exposure to QRD, HRD and RD of oxamyl only and with Injo200 or 1000ppm of Huwa-San TR50, respectively. Adding 1000ppm of Huwa-San TR50 to QRD, HRD and RD of oxamyl was found to significantly increase the toxicity of oxamyl to all developmental stages of O. afrasiaticus, whereas, the RD of Injo200 had no significant toxic effect on O. afrasiaticus with or without oxamyl. This does not mean that Injo200 is useless but it might be very effective on other pests rather than O. afrasiaticus. Finally, this study has provided a new acaricide that can be effectively used in controlling O. afrasiaticus. This includes the new approach of mixing Huwa-San TR50 with oxamyl which significantly increases its effectiveness against O. afrasiaticus. This approach can help not only in reducing control cost but also in reducing residual effects of acaricides on date fruits.