Plant Protection
Year:2015 | Volume:38 | Issue:2 |Papers Count:10

Alfalfa with 78631 hectares area in East Azarbaijan province and approximately 6410 hectares in Ahar region is an important field crop in this area. There was no compre-hensive research about the plant parasitic nematodes associated with alfalfa, therefore during 2002-2003, 33 soil samples were collected from alfalfa fields of several locations in alfalfa fields in Ahar region, partly biodiversity plant parasitic nematodes in this crop were identified.Nematodes were extracted by combined sieving and centrifugal-floatation and were transferred to glycerin method. After preparation, microscopic slides were examined under the light microscope. Measurements and drawing of nematodes were carried out using a drawing tube equipped with the micro¬scope. Different species were identified on the basis of morphological characters as well as morphometric parameters and available literature. In this survey, 20 species of 11 genera belonging to suborder Tylenchina included:Boleodorus thylactus, Coslenchus aquaticus, Criconemella antipolitana, Ditylenchus dipsaci, Ditylenchus medicaginis, Geocenamus brevidens, Geocenamus nanus, Geocenamus quadrifer, Helicotylenchus digonicus, Helicotylenchus pseudorobustus, Helicotylenchus, Paratylenchus italiensis, Paratylenchus tateae, Pratylenchus scribneri, Pratylenchus neglectus, Pratylenchus thornei, Psilenchus iranicus, Tylenchorhynchus parvus, Tylenchorhynchus striatus, Zygotylenchus guevarai were identified. Finally, Coslenchus aquaticus and Tylenchorhynchus striatus are new records of plant parasitic nematodes fauna from Iran.

The leaf gall midge is a serious pest of mango in Baluchestan. Mango leaf gall midge produces wart-like galls on leaves resulting in reduced photosynthesis, leading to leaf drop and lowered fruit production. Younger trees may die while older trees fail to recover normal growth after repeated attacks. In Kahir village a field experiment was conducted to test the efficacy of Five insecticides alone and in combination with oil against the mango leaf gall midge, when the new leaves sprouted. The treatments were Abamectin EC1.8%, Dimethoate EC40%, Malathion EC57%, Cyromazine WP75% and Acetamipride SP20%. In this study a completely random blocks design with 11 treatment and 4 replicates were tested in 2 years. To evaluate the effectiveness of the insecticides, the number of galls on the leaves was counted one day before spraying, 5 and 14 days after spraying. The results of insecticides application in two years showed a significant difference among treatments at level of 5%. Insecticides used were effective in reducing pest populations. Fourteen days after spraying of insecticides excellent control was obtained with Malathion alone (93.76%) and in combination with oil (98.75%) and trigard cyromazine (91.48%) in first year. Fourteen days after spraying of insecticides excellent control was obtained with Malathion alone (93.93%) and in combination with oil (94.90%) and trigard cyromazine (82.42%), Dimethoat (83.65%) and Acetamipride (83.12%) in second year. while one percent volk oil was markedly less effective.

The two-spotted spider mite, Tetranychus urticae Koch, is one of the major pests with a wide host range in the world. Host plants and plant varieties could be a factor influencing the biological and reproductive properties of pests. The effect of 12 cotton commercial cultivars, including Avangard, B557, Belli isovas, Chegvara, Khordad, 010, Opal, Sahel, Shirpan 539, Tashkand, Varamin and Varamin 349 on biological and reproductive parameters of T. urticae was investigated under laboratory conditions, 25±1oC, 65±5% RH, and photoperiod of 16:8 (L:D) hour. The longest female immature period was observed on 010 (13.70 days) and the shortest period was on Khordad cultivar (10.06 days). The longest and shortest female adult longevities were on Shirpan539 (18.70 days) and Opal (9.30 days), respectively. The life expectancy of one-day-old adult of two-spotted spider mite was estimated to be 13.30, 11.95, 12.45, 16.30, 16.80, 8.45, 8.17, 12.85, 17.82, 10.41, 11.10 and 18.20 days on the respected cultivars. The net fecundity rate was 33.96, 39.64, 41.70, 50.09, 49.09, 11.21, 5.19, 43.07, 41.47, 6.69, 14.62, and 82.03 eggs/female on the above-mentioned cultivars, respectively. Moreover, the highest and lowest values of the net fecundity rate was on Belli isovas (83.45 eggs /female) and Opal (5.81 eggs/female), respectively. Comparison of the achieved results on the tested cotton cultivars revealed that Varamin 349 is the susceptible cultivar and the Opal cultivar is a relative resistant cultivar against T. urticae. These findings could be considered in planning of an integrated pest management program of this mite.

The greenhouse whitefly, Trialeurodes vaporariorum is an important pest in vegetable and ornamental crop, especially in greenhouse condition. The predatory mite Amblyseius swirskii has been evaluated as a potential biological control agent for whiteflies. Functional response and mutual interference of adult female of this predator fed on young instars (first + second instar) of greenhouse whitefly were studied in laboratory conditions (25±1oC, 70±10 % RH, and a photoperiod of 16:8 h L:D). The experiments were carried out on leaf disks in petri dishes with 10-15 replicates. SAS program was used to determine the type of functional responses and estimate the functional responses parameters. Our results revealed that adult females of A. swirskii exhibited type II functional responses on different densities (2, 4, 6, 8, 12, 20, and 30) of prey. The rate of searching efficiency and handling time were estimated as 0.142±0.022 h-1 and 2.310±0.110 h, respectively. Nicholson’s model and linear regression were used to determine the per capita searching efficiency and interference coefficient, respectively. The per Capita searching efficiencies of this predator decreased significantly with increasing predator densities and the value of interference coefficient of this predator fed on 40 density of greenhouse whitefly was -0.167. The rate of predation increased as the host density increased from 2 to 30 and subsequently the predator density decreased from 6 to 1. Therefore, different host-predator ratios could affect the efficacy of A. swirskii

In this study different characters of powdery mildew of alfalfa were investigated in natural resources around Boroujerd in Lourestan province. The fungi species, disease severity, ascospore as primary inoculums, percent of germination of conidia, chemical analysis of non-infected and infected plants, overwintering manner of fungi and correlation of plant phonologic period with fungi growth organs were studied. The fungi were identified as Leveillula taurica (Lev.) Arnaud. The mean of the disease severity on upper and lower leave surfaces was 12.13±2.4 and 39.32±3.81 percent, respectively. Between disease severity on upper and lower surface of leaves there was a positive and significant correlation (r= 46.4) & (p<0.01). Liberation of ascospore increased from bigining of liberation until infection time. It was determined that ascospore was the primary infection source. Also, the best temperature and time for germination of conidia was 100.C and 72 hour and there was not any statistically significant difference between 3 temperatures of 10, 15 and 200.C (p<0.01). Between dried mater and ether extract of non-infected and infected plants there was not any statistical significant differences, but between the crude protein, crude fiber and ash of non-infected and infected plant there was a significant difference (p<0.05). The growth of fungi on plant began 5 days after June. The mean height of plants was 55.25 cm and at green stage of plant and the sexual stages, the growth of fungi completed 6 days after the September when the seeds of plant fell on the ground.

Verticilium wilt of olive, caused by Verticillium dahliae, is a devastating disease of olive which can reduce the yield and may kill eventually the infected olive trees by destructing of their vascular system. In this research, some wood sampels of olive trees in Tarom showing wilting symptoms were collected. The causal fungus was isolated on Czapek medium. Total DNA of V.dahliae isolates was extracted using CTAB method with minor modifications. For evaluation of reaction of olive cultivars to the fungus, 5-months old roots saplings of four olive cultivars including: Zard, Arbequin, Oblonga and Koroneiky were inoculated with suspension of 107 spores/ml of a D isolate using root deep inoculation. Total DNA of inoculated plants were isolated immediately after inoculation with the fungus and then 2, 7, 15, 27, 41, 56, 77 days after inoculation. The real-time PCR with the SYBR Green, was applied on the total DNA extracted from infected olives at different stages of infection. Results of quantification of V.dahliae genomic DNA in total genomic DNA isolated from infected olives sampled at different times showed that the amounts of DNA of pathogen in the roots of Zard and Arbequin cultivars increased faster than in Oblonga and Koroneiky. The fungus had more restrictions with colonizing of roots of Koroneiky, rather than other cultivars. In the root system of "Zard" cultivar however, fungus colonized the roots faster than other cultivars. The results of this research also showed that Real time PCR can be used as an efficient way of screening olive genotypes for resistance to Verticillium wilt.

The effect of parasitism in aphid population growth depends on the pattern of host instar selection. Patterns of preference may vary with the physiological state, including egg load, age and also size of female foragers. In this study, the effect of age and size of Lysiphlebus fabarum (Braconidae: Aphidiinae) females (asexual population) on host instar preference (Aphis fabae Scopoli), were studied. For this purpose, a cohort of females (1-day old, n=30) were introduced separately to 30 black bean aphid including (10 1st, 10 2nd, and 10 4th instar aphids). After 2 days, these females were introduced again, into host patches with previous conditions. In other test, small and large wasps (n=30) were introduced to 30 host aphids, with previous conditions. At the end of two tests, number of mummies formed, emergence rate and proportion of emerged offspring were determined. According to analysis, there was significant difference in number of mummies and proportion of emerged adults in fourth instar nymph between mothers with 1-day and 3-days old, such that in 1-day females were more than 3-days old ones. There was difference significant in emergence rate of offspring between small and large wasps at first and fourth instars. Furthermore, in small and large wasps, the number of mummies and proportion of emerged adults on first instar nymph was more than other instars significantly, whereas maternal size had no effect on host preference. This study showed that L. fabarum females in both ages and sizes, preferred first instar nymph than other stages.

Essential oils have been used as alternatives to chemical pesticides. In this study, fumigant toxicity of cumin essential oil, Cuminum cyminum (L.) was investigated on the adults of granary weevil, Sitophilus granarius (L.) and confused flour beetle, Tribolium confusum Jacquelin du Val. Experiments were conducted at 25±1 and 32±1oC, 5±55 relative humidity and darkness with four replications. Cumin essential oil was applied for S. granarius at the concentrations of 4, 7, 10, 13 and 16 mL L-1 air and in the case of T. confusum, 8, 11, 14, 17 and 20 mL L-1 air. Adult mortality was counted 24 and 48 hours after exposure. The results showed that an increase in temperature and exposure time increased both insects mortality. Also, S. granarius adults were more susceptible than T. confusum. Adult locomotor activity was studied at both temperatures by application SwisTrack version3. Distance and speed of insects when exposed to the cumin oil at a temperature of 32 ± 1°C was significantly more than cumin oil + 25±1oC. Therefore, combination of essential oils and heat can be used in integrated pest management programs of stored products.

Plant essential oils as low toxic agents to mammals and non-target insects have been used against diverse insect pests. The present study was conducted to determine the contact and fumigant toxicity of essential oils of Artemisia absinthium L. and Salvia pratensis L. against Tribolium castaneum (Herbst) (Tenebrionidae) and Callosobruchus maculatus (F.) (Bruchidae) adults. Isooctyl phthalate (39.39%) and a-monopalmitin (16.71%) for A. absinthium and dodecane (30.42%) and tridecane (12.10%) for S. pratensis were identified as major components of essential oils by gas chromatography and mass spectrometry. Bioassays revealed that all essential oils had strong contact and fumigant toxicity on the experimental insects. Essential oil of A. absinthium with LC50 of 8.518 (10.033-7.093) ml/1 had significantly higher fumigant toxicity on T. castaneum than S. pratensis (LC50=12.539 (11.121-13.904) ml/1) after 72 h. In the case of C. maculatus because of overlapping of the confidence limits the observed difference was not significant. In contact toxicity of A. absinthium oil, T. castaneum with LC50=0.150 (0.117-0.196) ml/cm2 was more susceptible than C. maculatus with LC50=0.281 (0.230-0.356), ml/cm2. A direct relationship was observed between mortality rate and essential oil concentration and exposure time. Regarding the high toxicity of essential oils of A. absinthium and S. pratensis against T. castaneum and C. maculatus, it can be concluded that theses essential oils can be used in management of these insect pests.

Beetles of Carabidae or ground beetles are one of the most well-known groups of Coleoptera. Most of them are considerable predators of common agriculture pests. Because of the vast and diverse agriculture areas in Jiroft, we studied the fauna of Carabidae in different agriculture crop lands of Jiroft. Different methods such as hand picking, pit fall traps and light traps were used in this study, during 2012-2013. In total, 30 species and subspecies belonging to 21 genera and 10 subfamilies of carabid beetles were collected and identified. Most of the species were collected by pit fall traps. One species of the genus Acinopus was new for science, but needs further examinations. All species, except 7 were new to the fauna of Kerman province. Sampling in two climatically different, but geographically close (75kms) regions showed that species diversity differed between two regions. The species Pheropsophus (Stenaptinus) arabicus had the highest density among collected species. Regarding the role of habitat management in protecting natural enemies such as ground beetles, it is suggested that providing places as refugies for such insects in field boundaries and preventing application of pesticides can protect such insects and enhance their species diversity.