Foraging behavior of Aphidius matricariae (Hymenoptera: Braconidae) on tobacco aphid, Myzus persicae nicotianae (Hemiptera: Aphididae).

The aim of this study was to investigate the foraging behavior of Aphidius matricariae (Haliday) (Hymenoptera: Braconidae) as a biological control agent of Myzus persicae nicotianae Blackman (Hemiptera: Aphididae), a key and cosmopolitan pest of tobacco fields. To achieve a strategy for the control of this pest and a mass-rearing program of the parasitoid, host stage preference, switching, functional response, and mutual interference of A. matricariae were investigated at 25 ± 1°C, 70 ± 5% RH and 16:8 h L:D photoperiod. The parasitoid showed a preference for third- and fourth-instar nymphs of tobacco aphid in both choice and no-choice experiments. Using the Murdach's model, switching behavior was observed in A. matricariae between different density proportions of third- and fourth-instar nymphs. Further, the parasitoid exhibited a type II functional response when it was offered to third-instar nymphs of M. persicae nicotianae at six densities (2, 4, 8, 16, 32, and 64). Based on the linear regression analysis, there was a significance difference between the logarithm of per capita searching efficiency and the logarithm of parasitoid density. As the wasp density increased, per capita searching efficiency decreased. The result of this study revealed that A. matricariae is an effective agent in the integrated management of M. persicae nicotianae. In addition, application of these results can be important in mass-rearing program of A. matricariae.

The efficiency of Amblyseius swirskii in control of Tetranychus urticae and Trialeurodes vaporariorum is affected by various factors.

Amblyseius swirskii Athias-Henriot is a well-known predator that is used for controlling the population of two-spotted spider mites (TSSM), Tetranychus urticae Koch, and greenhouse whitefly (GHWF), Trialeurodes vaporariorum Westwood, in strawberry greenhouses. To find the effective factors that influence the efficiency of this predator, the predation rates of A. swirskii fed on (Ι) TSSM in the presence and absence of the pollen, webbing, and GHWF, as well as on (II) GHWF in the presence and absence of the pollen, and GHWF-produced honeydew were determined. Furthermore, developmental time, fecundity, and population growth rate of this predator under the same conditions were measured. Our results showed that A. swirskii was able to reduce TSSM population, while the spider mite webbing had an adverse effect on the performance of the predator. Therefore, the presence of the predator population at the time of the infestation is crucial to the success of biological control. It can be concluded that the alternative food sources such as pollen and GHWF-produced honeydew play an important role in maintaining the predator population in the absence of pests. Moreover, the results indicate that using the pollen and another pest along with the target pest can promote the predator density. A. swirskii consumed lower numbers of TSSM when concurrently offered with GHWF and/or maize pollen, and lower numbers of GHWF in the presence of pollen. On the other hand, in the presence of alternative food or alternative prey, the fecundity of the predator was much higher.

Age-Specific Functional Response of Aphidius matricariae and Praon volucre (Hymenoptera: Braconidae) on Myzus persicae (Hemiptera: Aphididae).

The green peach aphid, Myzus persicae (Sulzer), is one of the most important aphid pests on pepper. Aphidius matricariae Haliday and Praon volucre (Haliday) are known as biological control agents for aphids in vegetable crops. In this research, age-specific functional responses of these two parasitoids were evaluated on different densities of 2, 4, 8, 16, 32, and 64 green peach aphids. Type of functional response varied from type II to type III for different ages of A. matricariae, but type of functional response was not affected by female age for P. volucre. The functional response of P. volucre was determined as type II in the whole parasitoid lifetime. The searching efficiency (a), b, and handling time (T h ) were estimated using the Rogers equations. The highest searching efficiency (a) and lowest handling time were observed during the first half of lifetime of A. matricariae and P. volucre. Aphidius matricariae and P. volucre caused reasonable mortality of the green peach aphid by parasitism of 52.17 and 47.05 host aphids, respectively, in 24 h. Therefore, they are suggested as suitable candidates for control of M. persicae in pepper greenhouses.

Repellent and fumigant toxicity of essential oil from Thymus persicus against Tribolium castaneum and Callosobruchus maculatus.

Repellent and insecticidal activity of the essential oil extracted from Thymus persicus (Roniger ex Reach. F.) Jalas was evaluated against two stored-product beetles Tribolium castaneum (Herbst) and Callosobruchus maculatus (F.). Dry flowering aerial parts of the plant were subjected to hydro distillation using a modified Clevenger-type apparatus. The repellent and fumigant toxicity were tested against 1-7 days old adult beetles at 27 +/- 1 degrees C and 65 +/- 5% RH in dark condition. The repellency on C. maculatus and T. castaneum at highest concentration (2 microL/mL acetone) was 82.40% and 70.40% respectively. Fumigation bioassays showed that C. maculatus adults were significantly more susceptible (LC50 = 2.39 microL/L air) to the essential oil than T. castaneum adults (LC50 = 234.42 microL/L air). It could be concluded that T. persicus may have potential for applications in management of stored-product pests because of its safety, strong repellency and fumigant toxicity.

Demographic parameters of wrinkling aphid of pistachio leaf, Forda hirsuta Mordv. (Hem.:Pemphigidae) insitu of Rafsanjan's orchards.

Wrinkling aphid of pistachio leaf, Forda hirsuta Mordv. (Hem.:Pemphigidae) is one of the pests of pistachio trees. This aphid caused the shrinkage, thickening, and changing the color of the pistachio leaves. Since insect feeds from leave edges, the thick and rolled upward wrinkles were formed, which its green color turned into red. Therefore, its economical damages are out of direct feeding from plant extraction, twisting pistachio leaves, and the decrease of photosynthesis. In this research two orchards and 10 trees that each of them were selected in Rafsanjan region and 58 fundatrix galls, 120 nymphal galls were marked and the demographic parameters for apterus parthenogenesis female of this aphid were calculated via daily observations. The results indicated that intrinsic rates of increase (r) for 1, 2 and 3 generations were 0.01, 0.0638 and 0.0575 femal/femal/days respectively, Doubling time (DT) were 69.31, 10.52 and 12.04 days, respectively, net fecundity rates were 1.71, 11.5 and 7.37 femal/femal/days, respectively, Net fertility rates were 1.11, 8.87 and 5.01 days, respectively, and mean generation times (Tc) were calculated to be 31.5, 32.2 and 31.87 days, respectively. Other reproductive parameters such as gross hatch rate, gross fecundity rate, gross fertility rate, mean age gross fecundity and fertility, mean age net fecundity and fertility, mean age hatch, finite rate of increase (lambda), intrinsic birth rate (b) intrinsic death rate (d) and daily reproductive rate were also calculated. The results revealed that population parameters especially r in the first and second generations were lowest and highest, respectively and mean longevity of fundatrix was 30 days and the born nymphs made separate galls in the edge of pistachio leaves.