Thirteen of the most common lepidopteran-specific Cry proteins of Bacillus thuringiensis have been tested for their efficacy against newly hatched larvae of two populations of the spiny bollworm, Earias insulana. At a concentration of 100 μg of toxin per milliliter of artificial diet, six Cry toxins (Cry1Ca, Cry1Ea, Cry1Fa, Cry1Ja, Cry2Aa, and Cry2Ab) were not toxic at all. Cry1Aa, Cry1Ja, and Cry2Aa did not cause mortality but caused significant inhibition of growth. The other Cry toxins (Cry1Ab, Cry1Ac, Cry1Ba, Cry1Da, Cry1Ia, and Cry9Ca) were toxic to E. insulana larvae. The 50% lethal concentration values of these toxins ranged from 0.39 to 21.13 μg/ml (for Cry9Ca and Cry1Ia, respectively) for an E. insulana laboratory colony originating from Egypt and from 0.20 to 4.25 μg/ml (for Cry9Ca and Cry1Da, respectively) for a laboratory colony originating from Spain. The relative potencies of the toxins in the population from Egypt were highest for Cry9Ca and Cry1Ab, and they were both significantly more toxic than Cry1Ac and Cry1Ba, followed by Cry1Da and finally Cry1Ia. In the population from Spain, Cry9Ca was the most toxic, followed in decreasing order by Cry1Ac and Cry1Ba, and the least toxic was Cry1Da. Binding experiments were performed to test whether the toxic Cry proteins shared binding sites in this insect. 125I-labeled Cry1Ac and Cry1Ab and biotinylated Cry1Ba, Cry1Ia, and Cry9Ca showed specific binding to the brush border membrane vesicles from E. insulana. Competition binding experiments among these toxins showed that only Cry1Ab and Cry1Ac competed for the same binding sites, indicating a high possibility that this insect may develop cross-resistance to Cry1Ab upon exposure to Cry1Ac transgenic cotton but not to the other toxins tested.

Use of Bacillus thuringiensis toxins for control of the cotton pest earias insulana (Boisd.) (Lepidoptera: Noctuidae)

Detection of Theileria annulata by PCR and its Comparison With Smear Method in Native Carrier Cows

Incidence and faunistic composition of insect pests and the associated predators on roselle plants, Hibiscus sabdariffa L. have been studied during the 2002 and 2003 growing seasons in El-Kanater El-Khayria (about 30 km north Cairo), Kalubia governorate, Egypt. Fourteen phytophagous insect species and six insect predators were recorded. The dominance percentage of insect pests was found to be higher than those of the predators. The most dominant pests were the following piercing sucking insects Empoasca spp., Maconellicoccus hirsutus (Green), Aphis gossypii Glover, Bemisia tabaci (Genn.), Oxycarenus hyalinipennis (Costa) and Earias insulana (Boisd.). However, the most dominant predators were Polistes sp., Orius spp., Coccinella undecimpunctata and Scymnus interruptus. Also, results exhibited distinct compatibility between the abundance of the above mentioned pests and their associated predators. These results may indicate the importance of the recorded predators on biological control agents in su...

Insect pests and predators inhabiting roselle plants, Hibiscus sabdariffa L., a medicinal plant in Egypt

Infestation of Earias spp. on cotton and okra grown as monocrops and mix crops

Three roselle, Hibiscus sabdariffa L. varieties (Sudani, Masri and White) were cultivated at three different locations to recognize the transportation ability of roselle cultivation from the narrow old valley land to broad new land in Egypt. Qena as origin in situ old land, El-Kanater as ex situ old land and Nubaria as ex situ new land were the considered locations. Six growth quantitative characters and bolls infestation by spiny bollworm, Earias insulana were evaluated. Growth characters of roselle plants were affected significantly by either variety or location. Qena region was more suitable for roselle plant growth as judged with plant height, number of branches, number of fruits and sepals dry weight, followed by Nubaria followed by El-Kanater. Whereas, plants grown at Nubaria produced more fresh sepals weight than Qena or El-Kanater grown plants. As for Sudani, Nubaria exhibited the tallest plants, with the highest number of fruits and the heaviest fresh sepals as compared with the corresponding pla...

Effect of variety and location on growth and yield components of Roselle, HIbiscus sabdariffa L. and its infestation with the spiny bollworm Earias insulana (BOISD.)

S. Abul-Nasr

Papers

A study on the host plants of the spiny bollworm, Earias insulana (Boisd.) other than cotton and maize (Lepidoptera:Arctiidae).