Toxicity and physiological alterations were determined in Pseudococcus viburni nymphs treated with Artemisia annua methanolic extract. The leaf dipping bioassay showed LC50 values of 0.287% and 0.194% 24 and 48 hours post-exposure. Activities of general esterases were significantly higher in the control nymphs than in those which had been treated except for the 48 h time interval using α-naphtyl acetate. The activity of glutathione S-transferase using CDNB (1-chloro-2,4-dinitrobenzene) in the control nymphs, was significantly higher than in the control at both time intervals while no significant difference was observed after 24 h in addition to the higher enzymatic activity in the treated nymphs after 48 h. All three aminotransferases were significantly more active in the control nymphs except for time intervals of 24 h for γ-glutamyl transferase and 48 h for alanine aminotransferase. Higher activities of lactate dehydrogenase, acid- and alkaline phosphatase were found in the control nymphs than in treated nymphs for all time intervals. Activities of the enzymes involved in the antioxidant system including catalase, peroxidase, superoxide dismutase, ascorbate peroxidase and glucose-6-phosphate dehydrogenase was increased in the treated nymphs compared to the control. Results of the current study demonstrated toxic effects of A. annua methanolic extract on P. viburni nymphs causing mortality and physiological turbulences.

Aphids are one of the most important economic pests and vectors of viral diseases in crops. Brevicoryne brassicae L., one of the most serious aphid pests in Brassicaceae, if not controlled, often reaches very high densities. The present study compared the systemic effects of ethanolic, methanolic and aqueous Melia azedarach L., Peganum harmala L., Calendula officinalis L. and Otostegia persica Boissier extracts with two systemic pesticides, acetamiprid and pirimicarb (at the maximum label-recommended rate). Population growth percentages of B. brassicae through leaf spraying under greenhouse conditions were assessed. The chemicals were sprayed on one of the leaves in greenhouse condition. The results indicated that all the plant extracts have systemic effects at different levels. Among different extracts, O. persica ethanolic extract, P. harmala methanolic extract and M. azedarach aqueous extract resulted in a reduction of the B. brassicae population.

In this study, the effect of six commercial biocontrol strains, Bacillus pumilus INR7, B. megaterium P2, B. subtilis GB03, B. subtilis S, B. subtilis AS and B. subtilis BS and four indigenous strains Achromobacter sp. B124, Pseudomonas geniculate B19, Serratia marcescens B29 and B. simplex B21 and two plant defense inducers, methyl salicylate (Me-SA) and methyl jasmonate (Me-JA) were assessed on suppression of wheat take-all disease. Treatments were applied either as soil drench or sprayed on shoots. In the soil drench method, the highest disease suppression was achieved in treatment with strains INR7, GB03, B19 and AS along with two chemical inducers. Bacillus subtilis S, as the worst treatment, suppressed take-all severity up to 56%. Both chemical inducers and bacterial strains AS and P2 exhibited the highest effect on suppression of take-all disease in the shoot spray method. Bacillus subtilis S suppressed the disease severity up to 49% and was again the worst strain. The efficacy of strains GB03 and B19 decreased significantly in the shoot spray method compared to the soil drench application method. Our results showed that most treatments had the same effect on take-all disease when they were applied as soil drench or sprayed on aerial parts. This means that induction of plant defense was the main mechanism in suppressing take-all disease by the given rhizobacteria. It also revealed that plant growth was reduced when it was treated with chemical inducers. In contrast, rhizobacteria not only suppressed the disease, but also increased plant growth.