In the present study, 85 strains of actinomycetes were isolated from the neem tree (Azadirachta indica) and screened for their insecticidal activity against the green peach aphid, Myzus persicae. The results showed that crude extracts from 24 strains exerted a contact effect against M. persicae with different insecticidal efficacies. Crude extracts from 8 actinomycetes strains exhibited the highest insecticidal activity (above 60%). Out of these 8 strains, 3 isolates that produced the maximum mortalities were screened a second time. The crude extract from strain G30 was the most virulent against the green peach aphid, with LC 50 and LC 95 values of 1.680 mg/mL and 4.370 mg/mL, respectively, after 48 h of treatment. The following morphological, culture, physiological and biochemical characteristics of strain G30 were recorded: (i) ovateorbicular and smooth surface spores with short and curve filaments; (ii) an aerial off-white mycelium with a mustered yellow base; (iii) inability to produce soluble pigments; (iv) the ability to hydrolyze starch but not cellulose; (v) the ability to utilize glycerin and several sugars as a carbon source but not L-rhamnose and sorbitol. Molecular identification of G30 revealed a 99.6% genetic similarity of the 16S rDNA sequence with Streptomyces albidoflavus. We conclude that the isolate G30 was S. albidoflavus and that the insecticidal activity of its crude extract was sufficiently high to become a candidate for bioinsecticide development.

Poor seed‐set limits potential for soybean hybrid seed production. The objective of this study was to evaluate effects of different pollinators on the rate of seed set in three soybean cytoplasmic male sterile (CMS) lines, JLCMS9A, JLCMS82A, and JLCMS89A. The following five treatments were applied under net room isolation‐conditions: (i) insecticide application and release of alfalfa leafcutter bees (Megachile rotundata) during flowering; (ii) insecticide application in the absence of leafcutter bees; (iii) release of alfalfa leafcutter bees during flowering without insecticide application; (iv) the absence of insecticide or alfalfa leafcutter bees during flowering; (v) plants without a net cover and pesticide application. Results indicated that the rate of pod production and seed set differ significantly between CMS lines and between treatments. Alfalfa leafcutter bees were an effective pollinator as evidenced by increases in pod‐bearing rate and seed‐set rate respectively from 21.35 to 53.22% and from 19.91 to 58.77% in the three CMS lines. The three CMS lines also showed significant differences in seed set, with JLCMS82A exhibiting the highest rate in all five treatments, followed by JLCMS9A and then JLCMS89A. These results suggested that thrips (Sericothrips variabilis) might have some effect on soybean pollination, but did not elicit a major influence based on the low increases in seed production. The natural insect population served an important role in outcrossing and seed set in soybean.

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