Life history and reproductive parameters of the mango red spider mite, Oligonychus mangiferus (Rahman and Sapra) (Acari: Tetranychidae) were studied to investigate its response to different temperatures (25, 28 and 31 ºC), with 70 ± 5% R.H. on Mangifera indica L. Baladi variety in the laboratory. The results showed that the developmental time of the individuals shortened with increasing temperature. The total immature stages was the longest period (7.51 day for the female and 7.46 day for the male) at 25 ºC, while at 31°C was the shortest period (6.48 and 6.46 day, respectively). The life cycle was the longest period (12.18 day for the female and 11.71 day for the male) at 25 ºC, while at 31°C was the shortest period (10.78 and 10.38 day, respectively). So, the mean generation time was the longest (20.12 days) at 25 °C, followed by 28 °C (19.06 days) and then at 31°C was the shortest (17.87 days). On the contrary, total fecundity was 32.50 eggs (2.05 eggs/♀/day) at 25 ºC, then at 28 °C it reached 30.17 eggs (2.01 eggs/♀/day) and 26.83 eggs (1.93 eggs/♀/day) at 31°C, respectively. The mean generation time recorded the shortest (17.87 days) at 31°C, while the fecundity recorded the highest rate at 25 ºC (32.50 eggs; 2.05 eggs/♀/day). Based on these results, we can predict the presence of O. mangiferus on mango. Therefore, it should be easily to determine the best time to control this pest.

Laboratory trials were carried out to evaluate the influence of seven plant oils on population of two-spotted spider mite Tetranycus urticae Koch (Acari: Tetranychidae) at 30±1 ₒ C and 70% ±5 RH. The tested plant oils were Jatropha curcas (Jatropha), Eucalypts globulus (Camphor), linum vsitatissimum (Flax or Linen), Ricinus communis (Castor), Rophanus sativus (Radish), Lupinus termis (Lupine) and Alilum sativum (Garlic). The amounts of plant oils applied were 3, 4, 5, 6, 7, 8, 9 and 10ml. /liter. and sodium laurel sulfate (S.L.S) and Twen80 were used as solvents. The results revealed that, the Jatropha oil was the highest affective oil on the adult females of T. urticae in comparison with other six oils. The concentrations 8, 9 and 10ml. /l. gave high reduction percentages than the low concentrations for all plant oils. All oils were more effective after 72h. from spraying at high concentration. The S.L.S solvent was more effective than Twen80 and other seven tested oils at all concentrations.

The present study was conducted in the laboratory to assess the effects of two plant extracts (Jatropha curcas & Euphorbia lathyris) with four solvents (chlorophorm, ethyl acetone, acetone and methanol) on eggs and adult females of Tetranychus urticae Koch (Acari : Tetranychidae) at laboratory condition (27±2°C and 65±5% RH.). The results revealed that, the Jatropha curcas and Euphorbia lathyris gave high effected at concentrations 2.4 and 1.2% after 24, 48 and 72h. for adult females of T. urticae. While at concentration, 0.6% gave good results after 72 h. for the two extracts. Also, the concentration of 0.3% was not effective, except for J. curcas when used the acetone as a solvent. The acetone was the best solvent followed by chlorophorm and ethyl acetate. But, the solvent of methanol was not effective for the two plant extracts. The extract of J. curcas was more effective on eggs of T. urticae than the extract of E. lathyris; and the concentration of 2.4% was the best for its effect on eggs. However, the concentrations of 0.6 and 0.3% were slightly effective on eggs of T. urticae.

The terrestrial snail became economic serious pests attacking field corps, vegetables and orchards. This work was aimed to study the effect of some environmental factors on the biology of two species of land snails, Monacha obstructa and Eobania vermiculata. Results showed that, the soil types were markedly effective on fecundity and Ovipostion period of the land snails, M. obstructa and E. vermiculata. Clay and sandy loamy soils were favorable to such snail species, Whereas the general means of total clutches and eggs laid by one pair of both snails during the entire breeding season were (6.4 and 5.4 clutches and 211.4 and 271.6 eggs) and (6.36 and 6.36 clutches and 250.02 and 273.36 eggs) for M. obstructa and E. vermiculata respectively. While the highest values of general means of clutch size were (50.29 and 42.94) for sandy loamy soil while, the highest oviposition period were recorded in clay soil with values (69.4 and 68 days) for the two land snails respectively. Also, soil moisture was effected on num ber of per clutch. The highest egg number were recorded at percentage 80% soil moisture (116.8 eggs for M.obstructa) and (89.67 eggs for E. vermiculata) On the other hand, data revealed that the eggs of the two species of snails did not hatch at 30°C. On other hand, the highest values of egg hatch were found at 15°C with values 81and 76% for M. obstructa and E, vermiculata respectively. As the temperature increased, the egg hatching was significantly decreased. It clear that eggs of snails are sensitive to high temperature and embryos died at 30°C.