Report of Eristalis similis (Diptera: Syrphidae) from Iran

During a survey conducted on Syrphidae fauna in Guilan province (Masuleh & Lakan) in August 2006, some species of the genus Eristalis Latreille were collected and identified, of which E. similis (Fallen) is newly reported from Iran. The identification was confirmed by Heikki Hippa, Swedish Musem of Natural History

Olfactory response of the predatory bug, Orius niger (Hem.: Anthocoridae) to Tetranychus urticae (Acari: Tetranychidae) on cucumber leaves treated or untreated by Beauveria bassiana

Olfactory experiments were performed to study the predation behavior of Orius niger Wolff (Hemiptera: Anthocoridae) on the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) in presence or absence of Beauveria bassiana (Bals.). The experiments were carried out with six day old female bugs by recording the predator direction towards each of the Y-tube olfactometer arms and through three dependent replicates consisted of 15 replicates each. The predatory bug showed a significant preference towards the odors related to infested cucumber leaves by T. urticae in the absence of fungus and when the predator received odors related to T. urticae infested leaves v.s. B.bassiana fungus treated, spider mite infested leaves (72 hours). There was no significant difference in the predator olfactory experiment when the alternative arms consisted of treated v.s. untreated spider mite infested cucumber leaves (0, 24 and 48 hours after treatment). The results showed the capacity of the predatory bug to recognize the patches infected by B.bassiana fungus and successfully avoiding it

Transmission possibility of the fungus Beauveria bassiana KCF102 by mating behavior between Sunn pest, Eurygaster integriceps (Hem.: Scutelleridae) adults

Horizontal transmission of an isolate of the etomopathogenic fungus, Beauveria bassiana KCF102, was examined by allowing inoculated Eurygaster integriceps Put. adults to mate with non-inoculated ones. In case of susceptibility to B. bassiana, there was no significant difference between the males and females. However, there was significant difference among treatments for mortality of non-inoculated adults. It meant horizontal transmission could be happened between the inoculated and non-inoculated adults. Recording no significant difference among the treatments of the inoculated males + non-inoculated males and treatment with inoculated females + non-inoculated males revealed that this kind of horizontal transmission was not merely due to the mating behavior, given that the same transmission could be existed between inoculated and non-inoculated males or between those of female adults. There was significant difference for mortality percentage of adults among the five body-part treatments, ranging from 16.6 to 48.9, with the highest mortality for total body treatment and the lowest one for the pronotum

A laboratory investigation on virulence of Metarhizium anisopliae on Thrips tabaci (Thys.: Thripidae) and its predator, Orius albidipennis (Hem.: Anthocoridae)

In the present study, virulence of three isolates of Metarhizium anisopliae (Ascomycota, Clavicipitaceae) were evaluated on the second instar larvae of the onion thrips, Thrips tabaci Lindman by using spray potter tower at six conidial concentrations of isolates (103-108 conidia/ml) with Thrips Entomopathogenic Bioassay System (TEBS) method. Causing the highest total mortality rate on thrips larvae and having the lowest LC50 value (2.3 Ã 104 conidia/ml), M. anisopliae EUT118 was selected as the highest virulent isolate. Afterwards, the susceptibility of female adults and 5th nymphs of Orius albidipennis (Reuter) was tested against this isolate of M. anisopliae without attendance of host. Results indicated that two stages of predator; female adults and 5th instar nymphs had similarly low susceptibilities to fungal infection. In general, our results revealed that the anthocorid predator, O. albidipennis was less affected by this isolate of fungus. As a result, these two biocontrol agents could be used both together in control programs of T. tabaci in greenhouses

Evaluation of the effect of MbNPV on cabbage moth, Plutella xylostella (Lep.: Plutellidae), in laboratory conditions

Cabbage moth, Plutella xylostella L., is the most important pest in cabbage and canola cultures in Iran. Nuclear polyhedrosis viruses are known as important natural enemies of this pest. Because of economic importance of cabbage moth and the necessity of its control, MbNPV (Baculoviridae) was chosen to evaluate its effect on cabbage moth. Experimental data showed that the virus had high virulence and could be considered as the important agent for the control of this insect. In infestation of egg surfaces with 1 Ã 105 PIB/ml of MbNPV, all of larvae died three days after hatching. The LC50 value for the second instar larvae of cabbage moth was calculated 11.99 PIB/mm2. The LT50 values for the same larvae with 19.5 and 47.86 PIB/mm2 doses of MbNPV were 7.16 and 6.11 days, respectively. Mean percentages of mortality with 47.86 PIB/mm2 for 2nd, 3rd and 4th instar larvae were 74.44, 42.78 and 11.11, respectively

Study on potential of some solid natural substances in production of Beauveria bassiana (Ascomycota, Cordycipitaceae) conidia

In this study, two fungus isolates, Beauveria bassiana EUT105 and B. bassiana EUT116, were evaluated for production of aerial conidia on wheat, wheat flour, wheat bran, rice flour, rice bran, rice paddy, millet and corn flour using two phasic liquid-solid system. Data analysis showed that there are significant differences among treatments (simple media) in both isolates. In B. bassiana EUT105, the maximum and minimum productions were achieved on wheat bran, 2.3 Ã 1010 conidia/g and on rice paddy, 1.5 Ã 109 conidia/g of medium, respectively. In B. bassiana EUT116, wheat bran with 6.1 Ã 109 conidia/g and millet with 8 Ã 108 conidia/g had the maximum and minimum productions, respectively. Effect of adding nutritional complementary compounds to the growth media was significant in increasing of conidial yield. Related results showed that adding permeate increased the production but molasses did not it in comparison with control in both isolates. Wheat bran plus permeate had the maximum production, 5 Ã 1010 and 4.6 Ã 1010 conidia/g in B. bassiana EUT105 and EUT116, respectively and minimum production was obtained with rice flour plus molasses, 1.5 Ã 108 and 6 Ã 108 conidia/g in B. bassiana EUT105 and EUT116, respectively

Isolation, characterization and toxicity of native Bacillus thuringiensis isolates from different hosts and habitats in Iran

Bacillus thuringiensis is a Gram-positive, aerobic, facultative anaerobic and endosporeforming bacterium. Different strains of this species have the ability to produce parasporal crystalline inclusions which are toxic to larvae of different insect orders and other invertebrates and cause rapid death of the host. To determine the importance of this species in microbial control, we collected native strains and studied their virulence on the diamondback moth, Plutella xylostella. More than 148 samples were collected from Alborz, Guilan and Mazandaran Provinces. Experimental samples, including soil samples from forests, fruit gardens, agricultural fields, diseased and dead larvae, were transferred to a laboratory in sterile plastic containers. For evaluating B. thuringiensis isolates virulence, a cabbage leaf dip method with 106 cell ⋅ ml–1 concentration of various Bt isolates was applied to diamondback moths. Larval mortality was recorded 72 h after treatment. Based on bioassay results, all isolates were classified into three high, medium and low virulence groups. Protein level characterization based on the SDS-PAGE gel analysis showed that two isolates from a high virulence group have proteins of high molecular masses of 121 and 109 kDa. Results revealed that there is a positive correlation between protein masses and virulence of isolates. In addition, this research introduced nine strains that are highly toxic to P. xylostella and would be valuable as insecticidal agents for controlling lepidopteran pests