Three insect growth regulators (IGR), the chitin synthesis inhibitors (CSI) teflubenzuron and hexaflumuron and the juvenile hormone mimic (JHM) pyriproxyfen, as well as the organophosphate (OP) pirimiphos-methyl, were evaluated for their activity against the cowpea weevil, Callosobruchus maculatus (F), in cowpea seeds stored for up to 8 months post-treatment. The initial activity data showed that, based on LC50 level, teflubenzuron had strong ovicidal activity (LC50 = 0.056 mg kg(-1)) followed by pirimiphos-methyl (1.82 mg kg(-1)) and pyriproxyfen (91.9 mg kg(-1)). The residual activity data showed that none of the IGRs tested had strong activity when applied at 200 mg kg(-1) in reducing the oviposition rates of C maculatus at various storage intervals up to 8 months post-treatment. However, teflubenzuron reduced adult emergence (F1 progeny), achieving control ranging from 96.2% at 1 month to 94.3% at 8 months. Hexaflumuron showed a similar trend in its residual activity, ranging between 93.8% control at 1 month to 88.2% control at 8 months post-treatment. However, pyriproxyfen was more active than the CSIs tested and caused complete suppression (100% control) of adult emergence at all storage intervals. Unlike the IGRs tested, pirimiphos-methyl applied at 25 mg kg(-1) was more effective in reducing oviposition rates of C maculatus up to 8 months post-treatment. A strong reduction of adult emergence was also observed at various bimonthly intervals (98.6% control at 1 month to 91.6% control at 8 months post-treatment). The persistence of hexaflumuron and pirimiphos-methyl in cowpea seeds was also studied over a period of 8 months. The loss of hexaflumuron residue in treated cowpeas (200 mg kg(-1)) was very slow during the first month post-treatment (4.43%). At the end of 8 months, the residue level had declined significantly to 46.4% of the initial applied rate. The loss of pirimiphos-methyl residue in treated cowpeas (25 mg kg(-1)) was relatively high during the first month post-treatment (36.7%) and increased to 81.6% after 8 months.

and 2015 seasons, to study the effect of sowing date (15 th of April, 1 st of May and 15 th of May) on grain yield of twenty rice genotypes, and infestation by Rhizopertha dominica (F.). Sowing date had significant effects on all studied characters in both years. The highest values of number of panicles per hill, number of filled grains per panicle, grain yield, hulling, milling and broken rice grain were recorded in the early sowing date. The number of days from seeding to maturity and number of unfilled spikelets per panicle were recorded in the decline trend, as sowing was delayed. Egyptian Hybrid Rice 1 produced the highest values of grain yield followed by Giza179, and Giza178. Sakha106 produced maximum values of hulling and milling percentages. Regarding to the susceptibility of rice varieties to insect infestation by lesser grain borer, R. dominica in storage, data showed that the

2011 and 2012 seasons. The objectives of this investigation is amid to study the genetic behavior of ten rice genotypes under three sowing dates (May1 st , May 15 th and May30 th), the effect of different sowing dates on grain quality characters, and on the infestation by stem borer and to evaluate the susceptibility of certain rice varieties against the infestation by Lesser grain borer, Rhizopertha dominica (F.). The tested genotypes were;

Laboratory and field studies were conducted to evaluate the effect of three inert dusts, diatomaceous earth, kaolin and katelsous as wheat grain protectants against some stored grain insects, i.e., Sitophilus oryzae, Rhizopertha domininca and Tribolium confusum. Inert dusts were mixed with wheat grain in the laboratory at different concentrations. Data obtained from the laboratory experiment showed that the LC50, s of diatomaceous earth, kaolin and katelsous were 0.234, 0.071 and 0.235% w/w, 6.033, 6.306 and 8.938% w/w and 0.495, 0.496 and 103.875% w/w against S. oryzae, R. dominica and T. confusum, respectively one day after treatment. Diatomaceous earth was more effective than the other tested materials where it achieved complete mortality for the three tested insects after two days of treatment at the rate of 0.5% w/w. Results also showed that kaolin and katelsous act slowly on the tested insects, where the higher rates of 8% w/w for kaolin and 0.4% w/w for katelsous gave complete mortality after one week post treatment. For the field study (at farmers , storages), the higher concentrations (0.5, 8 and 0.4% w/w) of the three dusts, diatomaceous earth, kaolin and katelsous, respectively obtained from laboratory experiment were admixed with wheat grain and stored for 4 months at the farms. For the field experiment, the results showed that diatomaceous earth gave 100%, 91.6% and 98.2% mortality against the three tested insects, respectively after 4 months of storage at a concentration of 0.5% w/w at 7 th day of exposure. Kaolin at 8% w/w showed that adult mortality decreased from 100% at zero time of storage after 5 days of exposure to 13.7%, 27.1% and 16.9 at 4 months of storage after the same period of exposure against the three tested insects respectively. At zero time of storage, katelsous at a rate of 0.4% w/w showed the percent mortalities of 100%, 100% and 95.7% against the three tested insects, respectively at 5 days of exposure. The residual effect after 4 months of storage decreased to 14.3%, 52.9% and 35.6% mortality against the three insects, respectively at the same time of exposure. In general the results obtained showed that the diatomaceous earth had the most activity followed by katelsous and kaolin against the three tested insects. Also, the degree of effectiveness decreased with the increasing of storage periods.

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