فصلنامه تحقیقات آفات گیاهی
سال سوم شماره 2 (تابستان 1392)

The Carabidae beetles with high predatory ability are one of the most important natural enemies to reduce pest populations. A study was carried out for collection and identification of Pterostichinae and Scaritinae subfamilies (Coleptera: Carabidae) in Guilan province, Northern Iran during 2012. In total 6 species belonging to 4 genera and 4 tribes were identified which all of them are as new records for the studied area. The list of identified species is as follow: Subfamily: Pterostichinae (Bonelli, 1810) Tribe: Pterostichini (Bonelli, 1810) 1.Pterostichus elongatus (Duftschmid, 1812) Tribe: Platynini (Bonelli, 1810) 2.Agonum angustatum (Dejean, 1928) Subfamily: Scaritinae (Bonelli, 1810) Tribe: Scaritini (Bonelli, 1810) 3.Scarites planus (Bonelli, 1813) 4.Scarites (Parallelomorphus) terricola (Bonelli, 1813) 5.Scarites procerus eurytus (Fischer von Waldheim, 1828) Tribe: Clivinini (Rafinasque, 1815) 6.Clivina laevifrons (Chaudoi,. 1842)

Sawtoothed grain beetle, Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae) is one of the major pests of stored products like stored wheat. In the current study, biology in laboratory, thermal requirements and population growth parameters of O. surinamensis were studied on five wheat varieties including Ghods, Mahdavi, Chamran, Kavir and Pishtaz. These experiments were carried out in growth chamber at 705% R.H and a photoperiod of 12 L: 12 D h.. Larval and pupal periods at 28±0.50C showed no significant difference on various varieties. Average oviposition rate of female on different varieties were also compared. Each female laid 105.11±8.28 and 72.72±4.34 eggs on Ghods and Kavir varieties, respectively, showing the highest and the lowest oviposition rates among varieties. Effect of temperature on growth rate of immature stages was also studied at 20, 25, 28 and 30°C on the five mentioned varieties. The results revealed that increasing temperature from 20 to 30°C. decreased the larval and pupal periods. The thermal requirements of sawtoothed grain beetle were studied on the five wheat varieties. by keeping the insects at 15, 20, 25, 28 30 and 35°C. The result showed the minimum larval T0 was occurred on Chamran variety and the maximum on Ghods. The lowest pupal T0 was observed on Pishtaz and the highest on Ghods. The lowest and the highest thermal constant of larval and pupal stage occurred on Ghods and Pishtaz, respectively. Comparison of population growth parameters revealed the highest (71.65 days) and the lowest (33.55 days) value of R0 was on Mahdavi and Kavir, respectively. In these conditions the highest and lowest values of rm were recorded on Mahdavi and Pishtaz varieties, respectively. The shortest doubling time (DT) (10.79 days) belonged to Mahdavi varietiy and the shortest generation time (65.16 days) was obtained on Chamran. The value of  showed no significant difference among varieties.

Lepidosaphes pistaciae Archangelskaya (Hem: Diaspididae) is an important pest of pistachio in sprayed orchards in Iran. This study was carried out to determine the local distribution of the parasitoids of pistachio oystershell scale in Isfahan Province, during 2003-2004 and to study the morphological characteristics of various developmental stages. A sampling program was conducted in five locations of pistachio production areas. In addition, some morphological characteristics of developmental stages in collected parasitoids were studied. As a result, four species were collected and identified from three locations of pistachio orchards. Among the parasitoids associated with L. pistaciae the female Coccobius annulicornis Ratzeburg was the internal parasitoids of L. pistaciae, while, the males fed on their own species as hyperparasitoids. Moreover, Zaomma lambinus (Walker) feeds as endo-hyperparasitoid on mature larval stage of endo-parasitoid and ecto-parasitoid and rarely on pupal stage of endo-parasitoid. It seems that Ablerus sp. feeds as ecto-hyperparasitoid on mature larval and pupal stages of endo-parasitoid.

Aelia acuminata (L.) (Hemiptera: Pentatomidae) is among cereal bugs that occasionally damages wheat and barley plants. To understand its reproductive potential, an experiment was carried out using adults of spring generation collected from a wheat field in Amol (North Iran). The insects were fed with wheat grains and maintained at 25 ± 1 ºC, RH = 60-80% and a photoperiod of L:D = 16:8 h. Development times of egg and five nymphal instars were 7.14 ± 0.028, 4.96 ± 0.056, 9.11 ± 0.221, 6.28 ± 0.238, 6.56 ± 0.185 and 8.63 ± 0.347 days, respectively. More than 80% mortality occurred during egg and two first nymphal stages. Total development time was not different between female (43.00 ± 0.87 days) and male (43.36 ± 0.81 days). Estimated values for intrinsic and finite rates of increase (day -1), gross and net reproductive rates (eggs) and generation time (days) were -0.0261 ± 0.0112,. 974 ± 0.210, 10.7 ± 5.81, 0.16 ± 0.094 and 68.99 ± 15.74, respectively. Poor reproductive performance of spring generation of A. acuminata indicated that they could not properly be established under the examined laboratory conditions.

Parasitoids of the genus, Trichogramma are the most widely used natural enemies for biological control of pests worldwide. The presence of flowering plants can improve efficiency of biological control agents by supplying sugar resource for parasitoids. In this study, two experiments were performed under laboratory condition (at 25±1ºC, 60±10% RH and a photoperiod 16L:8D), to evaluate the effect of buckwheat (Fagopyrum esculentum Moench) on biological characteristics of Trichogramma embryophagum (Hartig). The two conducted experiments were: 1) Study of biological characteristics of T. embryophagum in the first 24 hours after adult eclosion on floral plant buckwheat versus honey 10% and control (no feeding). 2) Study of the biological characteristics of T. embryophagum with continuous feeding on some nutritional resource as mentioned above during their adulthood. The angoumois grain moth, Sitotroga cereallela Olivier, eggs were used as a host in all experiments. In both experiments longevity was (3.26±0.22 and, 5.6±0.18 days, respectively) and number of host parasitized (36.8±2.78 and 63.36±1.6 eggs, respectively) of wasps in presence of buckwheat were significantly more than another treatment and control. In subsequent of laboratory experiments, a field survey was performed to evaluate T. embryophagum efficiency in presence of flowering buckwheat as an intercropping system with corn. Twenty sitocards were randomly placed in treatment and control field as an egg trap. The mean number of parasitized Sitotroga eggs in each card by T. embryophagum in the corn field with buckwheat and control field was 19.91±5.58 and 4.33±1.13 eggs, respectively that were significantly different. The results clearly showed the significant effect of flowering buckwheat on the efficiency of T. embryophagum that could be useful to develop an inundative biological control program using Trichogramma.

Ants (Hymenoptera: Formicidae) can interfere with biological control of scale insects through protecting them against natural enemies. This study was carried out to investigate the impact of Lasius turcicus Santschi on feeding and functional response of vedalia beetle, Rodalia cardinalis on sour orange saplings in a citrus orchard in Sari County, northern Iran, during 2010. A 2-3-day old third instar (L3) or female beetle with a certain number of worker ants (including 0, 2, 4, 6, 8 or 10) were confined on a leaf which infested with a certain density of third nymphal instars of Icerya purchasi Maskell (including, 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50). After 24 hours, the ant and ladybird were removed and the number of consumed scale was counted. The functional responses parameters were estimated using Rogers’ random predator equation. Results showed that the presence of ant on infested saplings decreased feeding of ladybird on scale. Mean daily feeding of females and third larval instars of ladybird decreased from 3.22 to 1.78 and 3.89 to 1.55 scales, respectively, while ant density increased from zero to 10 individuals per leaf. The functional response type was not affected by ant presence and a type II was observed in all treatments. In contrast, the values of functional response parameters were adversely affected by the ant activity. So that, by increasing ant density from zero to 10 individuals per leaf, the attack coefficient (a) of third larval instars of ladybird decreased from 0.143 to 0.009 and of adult females decreased from 0.0905 to 0.0002. After such increasing in ant density, handling times for third instars and adult females were increased from 6.84 to 10.79 and 7.36 to 10.04 hours, respectively. Because of adverse effects of this ant on feeding and functional response of R. cardinalis, its presence on citrus trees should be considered in biological control and integrated pest management program of cottony cushion scale in citrus orchards of northern Iran.

In a faunal study two ameroseid (Ameroseiidae) mite species were collected and indentified from Guilan province, Northern Iran during 2012-2013. The Ameroseius furcatus Karg, 1971 was collected from soil under unknown host plant in Damash region, Rudbar city (36° 45′ 16.49″ N, 49° 48′ 11.05″ E) and Epicriopsis palustris Karg, 1971 was collected from soil samples in Talesh (37° 21\' 54\" N, 50° 5\' 34\" E), Shaft (37° 9′ 24″ N, 49° 24′ 26″ E), Siahkal (36° 56′ 0″ N, 49° 54′ 0″ E), Fuman (37° 13′ 48″ N, 49° 17′ 24″ E) and Rostamabad (36° 53′ 54″ N, 49° 29′ 26″ E). The first species is new record for Iran mites fauna and second species is new record for Guilan province mites fauna. The collected specimens were identified by Dr. Peter Masan from Slovakia Academy of Sciences. Also a checklist of 22 known species of family Ameroseiidae recorded from Iran is provided.