Mirza Jawwad Hassan, Kamran Muhammad, Alatawi Fahad Jaber
Acarology Laboratory, Department of Plant Protection, College of Food and Agriculture Sciences, King Saud University, Riyadh 11451, Saudi Arabia.
Saudi J Biol Sci. 2021 Aug;28(8):4348-4357. doi: 10.1016/j.sjbs.2021.04.023. Epub 2021 Apr 17.
In the present study, we evaluated the effect of management practices, fruit season, host habitats (young and old fronds, date fruits and grasses), and temperature on the phenology and abundance of the date palm mite (DPM). The study was conducted in two date palm orchards (two plots each): a managed and an unmanaged plot. The phenology of DPM was assessed based on adult cumulative mite days (ACMDs), while mean mite density was used to assess the mite abundance on different host habitats. The ACMDs and mean mite density were significantly different between managed and unmanaged plots on different host habitats in both fruiting and off-seasons. The date fruits had highest ACMDs during fruiting season. While young fronds had significantly higher ACMDs than on old fronds an grasses during both seasons in both plots.. The temperature and season type significantly affected the mean density of DPM eggs and adults. There was a significant effect of host habitats mean density of DPM eggs and immatures. Based on the adult phenology and abundance of DPM, the mite overwinters in young fronds and aerial offshoots of infested date palm trees. These overwintering DPM caused the seasonal date fruit infestation, each year. Additionally, different phytophagous and predatory mites, which co-occur with DPM, and were found on different host habitats affected the phenology and abundance of DPM. Moreover, the change in DPM body color was related to the host habitat that they fed in. Exceptionally, the brown color of females collected during the winter season could be due to physiological changes due to low temperature. In DPM males collected from different host habitats throughout the study, some morphological variations in the width of the knob, height of the hook, and the angle between the knob axis and dorsal margin of the shaft were also recorded. The results of this study suggest that young fronds and grasses are the suitable sites for DPM survival and overwintering. Hence, the management practices, early in the fruit season and/or during off fruit winter months, should be directed towards these habitats. These could provide efficient reduction in seasonal infestation of DPM.
在本研究中，我们评估了管理措施、果实季节、寄主生境（幼嫩和老叶片、枣果和草）以及温度对枣椰螨（DPM）物候和数量的影响。该研究在两个枣椰园进行（每个枣椰园有两个地块）：一个是管理地块，一个是未管理地块。基于成螨累积螨日（ACMDs）评估DPM的物候，而平均螨密度用于评估不同寄主生境上的螨数量。在结果期和非结果期，管理地块和未管理地块在不同寄主生境上的ACMDs和平均螨密度存在显著差异。枣果在结果期的ACMDs最高。在两个地块的两个季节中，幼嫩叶片上的ACMDs均显著高于老叶片和草上的ACMDs。温度和季节类型对DPM卵和成虫的平均密度有显著影响。寄主生境对DPM卵和未成熟螨的平均密度有显著影响。基于DPM的成虫物候和数量，螨在受侵染枣椰树的幼嫩叶片和空中侧枝上过冬。这些越冬的DPM每年都会导致季节性的枣果侵染。此外，与DPM共生且在不同寄主生境上发现的不同植食性螨类和捕食性螨类影响了DPM的物候和数量。此外，DPM体色的变化与它们取食的寄主生境有关。例外的是，冬季采集的雌螨棕色可能是由于低温导致的生理变化。在整个研究过程中从不同寄主生境采集的DPM雄螨中，还记录到了瘤的宽度、钩的高度以及瘤轴与轴背缘之间角度的一些形态变异。本研究结果表明，幼嫩叶片和草是DPM生存和越冬的适宜场所。因此，在果实季节早期和/或果实淡季冬季月份的管理措施应针对这些生境。这可以有效减少DPM的季节性侵染。
