Comparative Demography of the Spider Mite, Oligonychus afrasiaticus, on four Date Palm Varieties in Southwestern Tunisia

The date palm mite, Oligonychus afrasiaticus (McGregor) (Acari: Tetranychidae), is a serious pest of palm date fruits. Life cycle, fecundity, and longevity of this mite were studied on fruits of four date palms, Phoenix dactylifera L. (Arecales: Arecaceae)(varieties: Deglet Noor, Alig, Kentichi, and Besser), under laboratory conditions at 27 = 1 °C, 60 ± 10% RH. Total development time of immature female was shorter on Deglet Noor fruits than on the other cultivars. O. afrasiaticus on Deglet Noor had the highest total fecundity per female, while low fecundity values occurred on Besser. The comparison of intrinsic rates of natural increase (rm), net reproductive rates (Ro), and the survival rates of immature stage of O. afrasiaticus on the host plants suggests that O. afrasiaticus performs better on Deglet Noor fruits. The mite feeding on Alig showed the lowest intrinsic rate of natural population increase (rm = 0.103 day 1). The estimation of difference in susceptibility of cultivars to O. afrasiaticus is crucial for developing efficient pest control programs. Indeed, less susceptible cultivars can either be left unsprayed or sprayed at low threshold

Some ancient practices used for agricultural pest control in Yemen

Agriculture in Yemen dates back at least 5000 years. As far as insects are concerned, some references to beekeeping date back to about 1000 BC. The history of insect collection in Yemen started in the 18th century, with the Danish expedition of Frederick V. Although this expedition ended tragically with most members dying of disease, its results were later published. As we follow the history of agriculture in Yemen we find that farmers developed a great store of knowledge, elaborated through ..

Experimental studies on occurrence of cereal aphids and resulting damage to small grain crops in southwestern Quebec.

Cereal aphids started to infest cereals in the first week of June and reached their peak in the second and third week of July. They could affect both the quantity and quality of grain yields, but I recommend chemical control only when the aphid population reaches the economic threshold level, which was calculated as 16 aphids/tiller. Pirimicarb is recommended for chemical control, as it controlled aphids efficiently and had a minimal effect on the available predators and parasites. A sequential sampling plan has been developed to detect if populations reach economic threshold. Temperature accumulation, starting from the first detection of aphids on the crop, allowed prediction of the time of peak population on the crop

Survey of the Coconut Palm Fruits Deformation in the Coast of Hadhramout and the Diagnosis of the Cause

The coast of Hadhramout is one of the most important coconut palm cultivation areas in Yemen, which occupy about 105 thousand acres. Since the end of the ninth decade of the nineteenth century, the phenomenon of deformation of coconut fruits began to spread and became a major problem for coconut palm farmers, and the cause was not diagnosed, so a survey and diagnostic study was carried out during the period from January to July 2018 and included 111 farms in the provinces of Hadhramout coast, famous with cultivation of coconut palms. The severity of infection was measured in 15 regions, after which the cause of this phenomenon was diagnosed. The results showed that most of the fruitful coconut palm farms that have been visited have symptoms of deformation of coconut fruits, and the infection rate fluctuated between 8 - 100%, with an average of 80% for districts, and this means that the phenomenon covers all coconut palm farms. Consequently, it is a problem pervaded all over regions and the injury severity was distributed throough five degrees of injury and the fifth degree was the highest (40%) followed by the fourth degree (29%), and the first degree which represents the healthy fruits, was 5% only. This means that the deformation phenomenon of coconut fruits was widespread in the districts of Hadhramout coast, and these symptoms have spread throw about 95%. The samples of eriophyid mites were diagnosed by the Insect and Acari Museum in Agriculture and Food faculty, King Saud University, Saudi Arabia. The results showed that the samples have coconut mite Aceria guerreronis Keifer

The evolution of insect biodiversity in Yemen

The Republic of Yemen is located in the southeast corner of the Arabian Peninsula, at 12-20oN and 41-54oE, and bordered to the north by Saudi Arabia, to the south by the Arabian Sea, to the east by Oman and to the west by the Red Sea and Bab al-Mandab. In the Red and Arabian seas are 112 islands, the biggest of which is Suqutrā. Yemen can be divided into four topographic regions: the coastal areas, the western highlands, the eastern plateau, and the Empty Quarter (al-Rubc al-Khalī), in additi..