Written by:
Assistant Professor Taha Mousa Mohammed Mansour AL-Sweedi
University of Karbala – College of Agriculture – Department of Plant Protection
The palm tree Phoenix dactylifera L., which is one of the most important plants belonging to the Palmaceae family in Iraq and in all places of its cultivation in the world, is exposed to many pathological and insect pests, causing it to have great and severe damages and is involved with many different factors other than the destruction of many of them, which causes Low numerical density and productivity of dates and other materials, and thus leads to a reduction of their economic importance. Oligonychus afrasiaticus (McGregor) is one of the pests that afflicts it. This type of mites is known by local names. It is known by the name of the ghabar spider in Iraq, the name Abu Farwa in Algeria, the name Arm in Sudan, the name of Ahbam in Egypt, the ghabar mites on the palms in Saudi Arabia, and the ghabar mites on the palms in Saudi Arabia. Palms in Yemen. The old world date mite was first described by Mcgregor in 1939 CE as Paratetranychus afrasiaticus (McG.), And later by Pritchard and Baker in 1955 to Oligonychus, the global name for the dust dream became O. afrasiaticus (McG.), In 1978 Krantz placed the last classification of the superfamily Tetranychoidea , which includes families with economic damage, including the Tetranychidae family to which the species Oligonychus belongs. In a study of the seasonal presence of the mammary roles on the field palm, he found the winter females Deutogyne, which began to appear on the wicker of the palm fronds, the rakub wicker, and the leaves of some plants in the gardens such as chrysanthemums when the temperature was higher than 17 ° C, and its presence was not noticed in the Habbouk stage, which is the first stage of the development of the palm fruit It is attributed to the presence of the tannin material in the proximal layer of the outer shell of the fruit, which gives it the astringent taste, in addition to the hardness of the outer shell, and at the Gamery and Khalal stages, the mite stages are concentrated around the fruit funnel and the tissue is secreted between the fennel stem and the funnel, and then covers the outer shell tissue of the vinegar, which impedes the physiological processes And it makes it preserving the green color covered with dust and shedding skins until the end of the season without turning to the other stages of the fruit, especially when the injury is severe. The mite stage has reached its peak in its preparation in the stage of the yellow passage due to the availability of appropriate environmental factors such as temperature and relative humidity and the availability of sufficient basic nutrients for its development, as at this stage there is a rapid increase in the accumulation of sucrose and a gradual decrease in acidity with a gradual increase in the proportion of soluble pectin In water and a decrease in the percentage of water and the characteristic color of the fruit, so it is yellow or red for some varieties, and this phase continues until the fruits begin to moisturize and the mites stages begin to decrease in their numbers in the wet and dates stages, and the reason for this is due to a decrease in temperature and to lack of food. The numbers of adult adults decreased to an absolute minimum, and the immature motile roles (larvae and nymphs) also completely disappeared when the temperature decreased to less than 17 ° C. The presence of the adults focused on the fallen fruits and the fronds of the palm fronds, the date palms, and the decoration palms (Washingtonia), which are characterized by their inability to feed and not accompanying the males, and their body appears to be covered with a white waxy layer.
Due to the lack of scientific studies conducted on this pest and the presence of other pests that took the interest of specialists in agriculture and farmers from the owners of the orchards, which led to the failure to circumvent the common mistake in naming this type of mite by farmers, and even from specialists in the field of plant protection by calling it the Ghabar spider This designation is a linguistic and scientific error in the field of studying this type of mites, and it is possible to clarify the phenotypic differences, habitats, and habits between spiders, which are known as Spiders, while the mites are known as Mites, and both of them belong to the articular division, but they differ in the subclass in their classification position In the zoonotic kingdom, the mites belong to the subclass: Acari, while the spiders belong to the real spiders, Subclass: Araneae, , As well as their difference in the phenotypic characteristics ) Figure1 ( , as the mites body is divided into the Gnathosoma area, the Idiosoma area and the Opisthosoma area, while the spiders’s body is divided into the cephalothorax, which is separate from the other area, which is the abdomen in the pedicle region, and this pedicle is not found in the mite’s body. It looks like a one-piece sac, and its mouthparts are found in the maxillary body region and are prominent to the outside, but in spiders most often they are found in a cavity inside the cephalothorax region, and spiders are considered carnivores, while the mites are varied in feeding and the number of legs for adult mites are four pairs, except for the family: Eriophyidae It has two pairs of legs .
The only forms in this designation may be that sometimes both mites and spiders may be present simultaneously on palm trees, and the spider web that resides on different parts of the palm is a manifestation of symptoms of infection with them, but we forget that spiders may be present on the palm tree and feed Only on the various animal pests present on the palms as they are carnivores, as for the ghabar mites , it secretes its spider web on the fruits of the palm and inserts its mouth parts in it to absorb the dissolved nutrients, which hinders its physiological processes, which leads to its non-transformation or development to the other growth stages of the palm fruit growth stages. The presence of this spider web may be the cause of this form of naming without paying attention to its source, whether it is a mite or spiders. This conclusion is supported by the presence of the spider web on the palm fruit that is affected by the ghabar mites with the presence of the spider or not, in addition to the lack of awareness that some species of the mite families produce web spidery.
Therefore, the designation of the Ghabar Mites as a Ghabar spider is scientifically incorrect, whether by specialists or local farmers, for the reasons mentioned above .
Figure (1):The difference between the body areas of the mites and the spiders. (A): represents the Mites (1) Gnathosoma, (2) Idiosoma (3) Opisthosoma (B) represents the spiders. (1) Four pairs of Legs (2) Cephalothorax (3) Abdomen (4) Pedicle area .
