JOURNAL OF CROP PROTECTION
Year:2017 | Volume:6 | Issue:3 |Papers Count:11

Trichoderma is one of the efficient biocontrol agents due to its high reproductive capacity, ability to survive under unfavorable conditions, efficiency in nutrient utilization, capacity to modify the rhizosphere, strong aggregativeness against the pathogenic fungi and efficiency in promoting plant growth and defense mechanisms. Therefore, the present investigation is carried out as an alternative practical and safe approach for mass multiplication of Trichoderma on different agro based media. Among them wheat straw and farmyard manure were found to be the best solid media supplemented with 10% wheat flour. The highest population count of Trichoderma species was observed in wheat straw. Antioxidant producing crops were also added to this carrier medium at a rate of 5g/kg in order to enhance the shelf life of propagules of Trichoderma species. Maximum population count wasobserved in soybean, maize and brown rice.

Citrus swallow tail butterfly, Papilio demoleus L. is a pest of citrus in many parts of the world. We examined the effect of four different citrus hosts including Citrus sinensis (L. ) (Tarocco and Valencia) Citrus limon (L. ) (Eureka), and Citrus paradisi Macfad. (Shambarg) on its life table parameters and biological characteristics at 24 ± 1 ° C, 75 ± 5% RH and a photoperiod of 16: 8 h (L: D). The developmental time of immature stages was longest on C. sinensis (Tarocco) (12. 3 ± SE days). The intrinsic rate of natural increase was significantly affected by various citrus, being the highest on C. sinensis (Tarocco) (0. 099 day-1) and lowest on C. sinensis (Valencia) (0. 011 day-1). The highest and lowest finite rates of increase were observed on C. sinensis (Tarocco) 1. 10 and C. sinensis (Valencia) 1. 01, respectively. The highest gross reproductive rate and the lowest mean generation time were observed on C. sinensis (Tarocco) and C. sinensis. (Valencia), respectively. The findings indicated that C. sinensis (Tarocco) appeared to be the most susceptible host to P. demoleus among the tested varieties. The results of this and similar studies in the future on other hosts may be considered as a basis for finding resistant host/hosts in monitoring this pest.

To investigate the effect of different fertilizers on yield and health related traits of pomegranate fruit, a field experiment was carried out during 2014 and 2015 seasons on six years old pomegranate trees cv. ‘ Bajestani’ growing in sandy loam soil under drip irrigation system in Khalilabad city, Khorasan, Iran. Organic fertilizers including: cow manure (25 kg/tree), vermicompost (5 kg/tree), and granulate humic (2 kg/tree) were applied without or with biofertilizers (azetobarvar, phosphobarvar and potabarvar at 1 liter/tree) by placement method. Results showed that plants treated with combination of organic and biofertilizers had higher yield and lower fruit drop than plants treated with organic fertilizers individually. The lowest fruit cracking (7. 5%, 2. 25%) as well as fruit infestation with Ectomyelois ceratoniae (Zeller) (27. 5%, 25. 34%) were observed in the plants treated with both biofertilizers and humic in 2014 and 2015, respectively. The most infestation to E. ceratoniae was observed in control treatment (38. 07%, 31. 44%) in both years, respectively. Fruit sunburn was not affected by nutrition of any type in both years. Results of leaf analysis revealed that plants treated by a combination of biofertilizer and humic had higher levels of macro and micronutrients compared with untreated plants. Altogether, our results suggest that biofertilizer in combination with organic fertilizers, especially granular humic, could be used in pomegranate orchards management to improve pomegranate yield, as well as to prevent crop losses resulting from cracking, nutrient deficiency and E. ceratoniae infestation.

Efficacy of the neonicotinoid insecticide, Calypso® was studied on eggs, nymphs and adults of Trialeurodes vaporariorum Westwood, using a leaf disc bioassay method. Concentrations from 0. 15 to 0. 8 ml/l were applied by systemic-contact method. Nymphs were more susceptible than eggs and adults, and LC50 and LC30 values were estimated to be 0. 465 and 0. 263 ml/l, respectively. Also, the longevity and fecundity of exposed females was reduced compared to control. Moreover, the demographic parameters were adversely influenced compared to control. The intrinsic rate of increase (rm) was significantly decreased to 0. 132 and 0. 139 day-1 at LC50 and LC30 level, compared to control (0. 152 day-1). Other life table parameters (R0, λ , T, and DT) were also significantly lower in the treated insects. Sublethal concentrations of Calypso® may reduce the insecticide residuals on greenhouse crops and reduce the resistance development in greenhouse whiteflies. Therefore, these concentrations may be applicable in the management of T. vaporariorum after complementary studies.

The common pistachio psyllid, Agonoscena pistaciae Burckhardt & Lauterer (Hemiptera: Psyllidae), is a key pest of pistachio trees in Iran. Both psyllid nymphs and adults directly damage pistachio; they extract large quantities of sap from tree and produce honeydew and cause deformation of leaves resulting in great economic damage. Little is known about the intraspecific variation of common pistachio psyllid in regions with stressed conditions, such as areas under high levels of pesticide application. Therefore, this study using geometric morphometrics was designed to 1) evaluate morphological differences in wing shape in populations under different levels of pesticide application in Kerman province as the main pistachio producer in the world, and 2) search for a link between the morphological data and previously studied molecular data. The populations were collected from regions with high and low pesticide applications. The results showed that wing shape (P < 0. 01) and size (P < 0. 01) are different between populations exposed to different chemical control programs. Based on the results, narrower wing shape was found in psyllid population in stressed environment (population with extreme chemical control programs). In spite of allometric growth, significant shape differences still remain when the data are adjusted to constant size, which showed the important role of genetic changes in the observed morphological changes. Moreover, links between morphologic and previously studied molecular data were revealed. Based on the results, it appears that an evolutionary resistance process is developing, therefore insecticide resistance management programs, in the regions under investigation, is recommended.

This study was done during 2012 to 2014 to determine the species composition of thrips on fruit trees and weeds of orchards in three counties of Qazvin Province (i. e. Buin-Zahra, Takestan and Qazvin). For each county 14 orchards were sampled. In each orchard, 10 trees and from each tree four shoots along with their leaves, flowers and fruits were selected as a sample unit. Diversity was calculated by Shannon-Wiener Index and evenness by Pielou evenness index. Species richness was estimated using the first-order jackknife richness estimator. One-way ANOVA was used to test whether there exists significant variation in species diversity, evenness and richness along the three counties. Of the 4, 489 adult collected specimens from three locations, 27 species belonging to 13 genera were identified. The highest number of thrips was collected on plants of family Rosaceae, followed by Vitaceae and Moraceae, respectively. The number of collected species in Qazvin (18) and Buin-Zahra (17) counties were more than Takestan (13) county. Similar trend was observed for the total number of adult specimens collected in the three counties as more specimens were found in Qazvin and Buin-Zahra than Takestan. Results of this study showed that Thrips tabaci L. was found on all species of fruit trees and weeds. There were no significant differences among the three counties in terms of both diversity (P = 0. 41) and evenness (P = 0. 45). Across the counties, thrips estimated richness was higher in Qazvin county compared to Buin-Zahra and Takestan counties. Among the trees in Buin-Zahra and Takestan counties, grape had the highest thrips diversity. The highest value of diversity for Qazvin county was recorded for apricot. The polyphagous species T. tabaci was dominant in all three counties, followed by Frankliniella occidentalis (Pergande) (in Qazvin county), Frankliniella intonsa (Trybom) (in Buin-Zahra county) and Frankliniella tenuicornis (Uzel) (in Takestan county).

The tomato leaf miner, Tuta absoluta (Meyrick) is an imported pest and serious threat to tomato production in farms and greenhouses of Iran. Use of genetically engineered plants expressing carbohydrase inhibitors is one of the non-chemical methods for controlling insect pests, and knowledge about enzymatic properties of carbohydrases will help us to achieve this goal. Therefore, in present study we characterized biochemical properties of digestive carbohydrases in the midgut of last larval instar of T. absoluta fed on different tomato cultivars (Kingston, Riogrande, Super Luna, Super Chief, Super strain B and Calj). While the highest amylolytic activity was on Super strain B, the lowest was on Super Chief. The optimal pH and temperature for α-amylase were found to be at pH 9. 0 and 45 ° C, respectively. As calculated from Lineweaver-Burk plots, the highest Km and Vmax values for α-amylase obtained in Super Chief and Super Luna cultivars were 0. 565 ± 0. 11mM and 2. 287 ± 0. 4mM/min, respectively. The effects of different compounds on amylolytic activity indicated that CaCl2, MgCl2, NaCl and KCl increased amylase activity, whereas EDTA, ZnCl2 and BaCl2 decreased the enzyme activity in Super Luna cultivar. The highest activity of α-/ß-glucosidases was observed at pH 6. 0 and 7. 0, respectively, whereas the optimal pH for α /ß-galactosidases was at 5. 0. The highest specific activity of α-/ß-glucosidases was determined in Riogrande-fed larvae, whereas the highest α /ß-galactosidases activity was in the larvae fed on Riogrande and Calj cultivars, respectively. By the native-PAGE, two bands were clearly detected for α-amylase. Since the larvae reared on Kingston showed lowest carbohydrase activities, this cultivar could possibly be suggested as the least suitable host for feeding of T. absoluta.

Aphis gossypii Glover is one of the major pests of cucumber in Iran. The effects of different concentrations of nitrogen (N1 = 0, N2 = 30, N3 = 60, N4 = 90 and N5 = 120 kg/ha), phosphorus (P1 = 0, P2 = 15 and P3 = 22. 5 kg/ha) and silicon (Si1 = 0, Si2 = 100 and Si3 = 200 kg/ha) on life table parameters of apterous morph of A. gossypii were studied. This study was conducted as factorial experiment based on RCD with nine replications in a growth chamber at temperature of 25 ± 3 ° C, 60 ± 5% relative humidity (RH) and a photoperiod of 16: 8 h (light: dark). The experiments were carried out using clip-cages that were fixed on leaves of cucumber growing in pots. According to the results, total fecundity of A. gossypii significantly was different among treatments and it was the highest on N1P2Si2 (64. 33 offspring) and the lowest on N3P2Si1 (22. 67 offspring). The lowest and the highest values of R0 were observed on N3P2Si1and N4P2Si2, respectively. The shortest mean generation time (T) was found on N4P1Si3 and the longest was on N5P3Si1. Furthermore, the lowest and the highest values of r were obtained on N5P3Si2 (0. 27 day-1) and N5P1Si1 (0. 41 day-1). Our results showed that in simultaneous application, the phosphorus had a more impact on life history and performance of cotton aphid.

The tribe Platylabini (Hymenoptera: Ichneumonidae, Ichneumoninae) of Alborz, Guilan and Tehran provinces (North central Iran) was taxonomically studied. The specimens were collected using Malaise traps during March to November 2010– 2011. Four species were identified including: Apaeleticus bellicosus Wesmael, 1845, Platylabus iridipennis Gravenhorst, 1829, Apaeleticus inimicus (Gravenhorst, 1820) and Linycus exhortator (Fabricius, 1787) of which A. inimicus and L. exhortator are recorded for the first time from Iran. An updated checklist of Platylabini in Iran, as well as diagnostic characters of the newly recorded species is presented.

Yellow (stripe) rust caused by Puccinia striiformis f. sp. tritici is an important disease that threatens wheat production where the weather conditions are congenial and susceptible cultivars are present. Host resistance is the most economical and environmentally safe control method to manage wheat yellow rust; and slow rusting resistance, a kind of quantitative resistance, has been reported to have more durability. We planned an experiment aimed to evaluate resistance durability to yellow rust in some wheat cultivars. This study was conducted in field plots under natural infection conditions against race(s) populations of stripe rust believed to have virulence against Yr2, Yr6, Yr7, Yr8, Yr9, Yr10, Yr17, Yr18, Yr21, Yr22, Yr23, Yr24, Yr25, Yr26, Yr27, Yr31, Yr32, YrA and YrSU resistance genes. Slow rusting parameters, including final rust severity (FRS), apparent infection rate (r), relative area under disease progress curve (rAUDPC), and coefficient of infection (CI) were evaluated in a set of 50 wheat genotypes along with susceptible control during a seven-year study from 2008 to 2014. Seedling reaction was also evaluated under field conditions. Based on evaluated resistance parameters, the cultivars (entries: 34, 40-50) as well as susceptible check with the highest values of FRS, CI, r and rAUDPC, were considered as susceptible cultivars. Eight cultivars (entries: 1-7and 9) were resistant at the seedling and adult plant stages. Thirteen cultivars (entries: 13, 15, 16, 17, 20, 21, 24, 28, 29, 32, 33, 35, 37) showed resistance reaction at the seedling, but susceptible to moderate reactions at the adult plant stage. Sixteen cultivars (entries: 8 10, 11, 12, 14, 18, 19, 22, 23, 25, 26, 27, 30, 31, 38, 39) were susceptible at the seedling stage, and had moderately resistant to moderately susceptible reactions at the adult plant stage. Accordingly, these later cultivars with low level of slow rusting parameters were supposed to have gene(s) for varying degrees of slow rusting resistance or high temperature adult plant (HTAP) resistance. The remaining cultivars may have low level of slow rusting resistance that need further study to elucidate their nature of resistance. Cluster analysis of wheat cultivars revealed four major groups/clusters, based on slow rusting resistance parameters and seedling infection types.

Rice yellow mottle virus (RYMV), endemic to Africa, is spread within and between rice fields by several species of Chrysomelid beetles and grasshoppers. In Tanzania and particularly in Morogoro, the virus is increasingly becoming a serious problem to rice production. The part of the field and developmental stage of rice at which RYMV vectors are predominantly abundant were not known since the need for the study. The assessment of population abundance of RYMV insect vectors were conducted in the three divisions of Mngeta, Ifakara and Mang’ ula of Kilombero district, in Morogoro Tanzania using sweep net in 4 m2 quadrats. Results revealed the highest abundance of two RYMV vectors, Oxya hyla Serville, 1831 and Chaetocnema sp, on the border parts of the rice fields rather than in the middle parts. The study established that the density of RYMV vectors was dependent on crop growth stages where the number of vectors increased with increase in crop age and it is concluded that the two insects are the main vectors of RYMV in the study area.