Yousif N. Aldryhim

Efficacy of the amorphous silica dust, Dryacide, against Tribolium confusum Duv. and Sitophilus granarius (L.) (Coleoptera: Tenebrionidae and Curculionidae)

Abstract Amorphous silica dust (Dryacide) was used to treat wheat at concentrations of 0, 250, 500, 750, and 1000 μg silica dust/g wheat. Adult Sitophilus granarius and Tribolium confusum were placed in the grain which was then incubated at 20 or 30°C and 40 or 60% r.h. Mortality counts were taken after 48 and 168 hr. S. granarius was more susceptible to silica dust than T. confusum under the same conditions. At the same temperature, the toxicity of silica dust to both species was more pronounced at 40 than 60% r.h. T. confusum was more tolerant to silica dust at 30 than at 20°C; whereas, S. granarius was more susceptible to it at 30 than 20°C. Silica dust reduced progeny 100% at 40% r.h. in all the concentrations that had been used. Progeny, however, were produced by S. granarius at 30°C and 60% r.h. but with significantly reduced numbers with increasing dosge. Silica dust had no adverse effect on wheat seed germination, wheat flour, and baking quality.

Combination of classes of wheat and environmental factors affecting the efficacy of amorphous silica dust, dryacide, against Rhyzopertha dominica (F.)

Abstract The effectiveness of amorphous silica dust (Dryacide) on three classes of wheat (Durum, hard wheat and soft wheat) was tested at 20°C and 30°C at 40% and 60% r.h. against adult and progeny of Rhyzopertha dominica (F.). The effectiveness of silica dust was generally greater at 30°C than 20°C and at 40% rather than 60% r.h. Toxicity of silica dust was significantly higher on durum at 40% r.h. and on hard wheat at 60% r.h. The optimum tested conditions for progeny production were 30°C and 60% r.h. The mean number of progeny produced was significantly reduced with increasing silica dust concentration from 0–500 μg silica dust/g wheat. However, increased silica dust concentration from 500–900 μg silica dust/g wheat had no increased adverse affect on progeny production.

Efficacy of gamma irradiation against Sitophilus granarius (L.) (Coleoptera: Curculionidae).

Abstract The lethal and sterilizing responses to gamma irradiation of eggs, larvae, pupae, and three-day- and four-week-old adults of Sitophilus granarius were investigated. Doses were 0, 10, 30, 50, 70, 100, 300 and 500 Gy. Eggs and larvae were unable to develop to adults following doses of 30–500 Gy. Emergence of adults from irradiated eggs and larvae occurred at a dose of 10 Gy. Pupae developed to the adult stage following doses of 10–70 Gy. A dose of 70 Gy at the pupal and four-week-old adult stages caused sterility. Three-day-old adults were most tolerant of irradiation and required 100 Gy for sterility. The percentage of damage to wheat grains caused by pre-adult stages following various irradiation doses was determined.

New Initiatives for Management of Red Palm Weevil Threats to Historical Arabian Date Palms

ABSTRACT The date palm is an important part of the religious, cultural, and economic heritage of the Arabian Peninsula. This heritage is threatened by the recent invasion of the red palm weevil (RPW) from Southeast Asia. In Saudi Arabia, a national campaign for control of RPW by containment/destruction of infested plants, injection and spraying of biochemical and chemical pesticide treatments in heavily infested and newly infested areas, and the use of pheromone/ kairomone traps for monitoring and reduction of RPW populations has been only partially successful in controlling its spread. New methods are needed to help manage the RPW populations. At a workshop in Riyadh in March 2010, plans were recommended to 1) devise and test new biological, chemical, and biotechnological methods to manage RPW in farms and urban palms; 2) compare the economic and logistic feasibility of acoustic and other detection methods against RPW larvae; and 3) develop biosensor indicators of RPW infestation in date palms. If these initiatives are successful, they will be of great assistance to landscape and orchard managers dealing with such a challenging pest of a highly valuable tree.

Irradiation of dates: insect disinfestation, microbial and chemical assessments, and use of thermoluminescence technique

Abstract Irradiation of dates (Khalas variety) at 0.9 kGy was sufficient to eliminate single insect infestation ( Oryzaephilus surinamensis ) and mixed infestation ( O . surinamensis and Tribolium castaneum ), whereas 0.3 kGy was effective only in controlling single infestation. Sensory properties were not affected but irradiation contributed to some reduction in microbial counts immediately after irradiation and counts remained low till the end of 6 months storage period. All sugars were significantly reduced immediately after irradiation but they increased gradually with increasing storage time. Thermoluminescence (TL) technique was useful in discriminating between irradiated and unirradiated dates during the entire storage period but was less sensitive as far as the dose estimation is concerned.

Diel Flight Activity Patterns of the Red Palm Weevil (Coleoptera: Curculionidae) as Monitored by Smart Traps

Abstract The red palm weevil, Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae), is a serious pest of palm in many subtropical and tropical regions of the world. Traps baited with aggregation pheromones are important management tools used to control this weevil. The daily flight activity patterns of the red palm weevil in Saudi Arabian date palm orchards were observed using smart traps (STs) with a catch period of 3 h (8 periods daily). Conventional bucket traps (CTs) were used for comparison. The capture efficiency of the STs was not significantly different from that of the CTs. A circular statistics analysis showed that the time of adult capture in the STs was nonrandom and indicated mainly diurnal activity; few adults were captured at night. The STs revealed differential activity between the sexes. The female activity pattern exhibited 2 strong peaks at 7 to 9 AM and 4 to 7 PM, and the 2nd peak was significantly higher than the 1st peak. The male activity pattern showed 3 peaks at 7 to 10 AM, 1 to 4 PM, and 4 to 7 PM with no significant differences among the peaks. Males initiated activity before the females. The number of adults captured by STs was positively correlated with the time of sunrise and wind velocity, negatively correlated with the time of sunset and the ambient temperature, and not significantly correlated with the relative humidity. Although these patterns were consistent during the study period, they differed from a variety of other patterns reported in European and Southern Asian environments, which suggests that R. ferrugineus has evolved considerable behavioral flexibility in coping with harsh environmental conditions typical of hot arid date production areas in Saudi Arabia. Knowledge of R. ferrugineus daily activity patterns in local field environments can help managers optimize the timing of pesticide applications and other control activities.

Biology, Predation, and Life Table of Cydnoseius negevi and Neoseiulus barkeri (Acari: Phytoseiidae) on the Old World Date Mite, Oligonychus afrasiaticus (Acari: Tetranychidae)

ABSTRACT. The old world date mite, Oligonychus afrasiaticus (McGregor) (Acari: Tetranychidae) is a severe spider mite pest of date palm in most of the Middle East and North Africa. Considering that nothing is known about the performance of phytoseiid predators against O. afrasiaticus, biology, predation, and life table parameters of Cydnoseius negevi (Swirski and Amitai) and Neoseiulus barkeri Hughes (Acari: Phytoseiidae), collected from date palm orchards, were studied under laboratory conditions (25, 35°C and 35 ± 10% RH) as a first step to understand their effectiveness against all mobile life stages of O. afrasiaticus. For both predators, oviposition period was significantly shorter at 35°C than at 25°C. The following parameters were obtained for C. negevi and N. barkeri at 25 and 35°C, respectively: female longevity, 31.8, 20.1, 35.7, 27.4 d; fecundity, 21.6, 38.0, 18.8, 34.8 eggs per female; oviposition period, 23.9, 13.7, 25.9, 18.1 d. Total predation of C. negevi and N. barkeri female was 246.0, 270.0, 227.6, 205.3 prey at 25 and 35°C, respectively. Rectal plugs were observed attached to the opisthosoma of some adult females of N. barkeri, which often cause the mite to stick to the surface. Life table parameters were estimated as net reproductive rate (R 0) 10.44, 17.35, 10.19, 13.84, intrinsic rate of increase (r m) 0.14, 0.19, 0.13, 0.16 d-1, finite rate of increase (&lgr;) 1.15, 1.21, 1.12, 1.17 d-1, generation time (T) 17.03, 15.17, 17.83, 16.61 d, doubling time (DT) 04.95, 03.64, 05.33, 04.33 d for C. negevi and N. barkeri at 25 and 35°C, respectively. The values of intrinsic rate of increase and net reproductive rate were higher in C. negevi than N. barkeri at both temperature regimes. Therefore, it could be concluded that C. negevi performance was better than N. barkeri against O. afrasiaticus and can be considered as a valuable addition to the existing methods for spider mites control.

Apterogyninae (Hymenoptera: Bradynobaenidae) from Saudi Arabia, with description of a new species

Eleven species in three genera from Saudi Arabia are listed. Macroocula riyadha Gadallah & Pagliano, spec. nov. is described and figured. Apterogyna mateui Giner Marí, 1945, Macroocula nitida nitida (Bischoff, 1920) are newly recorded from Arabian Peninsula and Saudi Arabia, Macroocula magna (Invrea, 1965) is newly recorded from Saudi Arabia.

Incidence of predatory phytoseiid mites in Saudi Arabia: new records and a key to the Saudi Arabian species (Acari: Mesostigmata: Gamasina)

Abstract Cydnoseius negevi (Swirski & Amitai, 1961), Neoseiulus paspalivorus (De Leon, 1957) and Proprioseiopsis beatus (Chaudhri, 1968) are reported for the first time from Saudi Arabia. The mite genus Cydnoseius Muma, 1967 is also new to the Saudi Arabian fauna. Cydnoseius negevi was collected from various host plants in three different regions (Riyadh, Hail, Eastern region) while N. paspalivorus and P. beatus were collected from Cynodon dactylon L. (Poaceae) in date palm orchards in Riyadh and Eastern region respectively. A key is provided to the adult females of the known species of Phytoseiidae of Saudi Arabia.

Insects Associated with Milkweed Calotropis procera (Ait.) Ait. in the Ibex Reserve in the Central Region of the Kingdom of Saudi Arabia

ABSTRACT: The insect fauna of the native milkweed plant Calotropis procera (Ait.) Ait. in the Ibex Reserve, in the Central Region of the Kingdom of Saudi Arabia was studied. Insects were sampled bimonthly from May 2007 to late April 2008, and then irregularly until June 2011. Ninety-nine insect species belonging to eight orders, 43 families and 80 genera were found to have some type of association with the plant during the period of sampling. The carpenter moth, Semitocossus Johannes (Staudinger), scale insect Contigaspis zilla (Hall) and milkweed aphid Aphis nerii (Boyer de Fonscolombe) were pests attacking the plant. Nine taxa collected represent new country records for Saudi Arabia: Clambus sp. (Coleoptera, Clambidae); Angiometopa sp. (Diptera, Sarcophagidae); Steleoneura sp. (Diptera: Tachinidae); Goniurellia longicauda Freidberg (Diptera, Tephritidae); P silochalcis sp. (Hymenoptera, Chalcididae); Odynerus blanchardianus Saussure (Hymenoptera, Chrysididae); Nomioides kenyensis Pesenko & Pauly (Hymenoptera, Halictidae); Cremastus aegyptiacus Szepligeti (Hymenoptera, Ichneumonidae) and Cerceris chlorotica Spinola (Hymenoptera, Sphecidae).