Journal of Applied Research in Plant Protection
Year:2018 | Volume:7 | Issue:1 |Papers Count:12

Fusarium, a phytopathogenic fungus in fields of corn, not only reduces the quality and quantity of crops but also causes food contamination and endangers people ̓ s health by producing some mycotoxins such as Fumonisin (FUM). In the present study, samples were collected from fungal disease symptoms-showing corn from different livestock and poultry storage in Khorasan-Razavi province. Having placed the corn on PDA and WA, isolates belonging to Fusarium genus were isolated and purified. As a result, a total of 40 isolates were obtained among which three species were identified as Fusarium verticillioides, F. graminearum and F. proliferatum with isolated frequencies of 34, 4 and 2, respectively. To support these results, DNA was extracted from the isolates from corn seeds and the fungal ribosomal DNA was amplified using PCR with species-specific primers. In addition, using PCR with the specific primers (FUM1 F/R) 15 isolates of F. verticillioides, as the prevalent species were examined for fumonisin production. The results indicated that all of the examined F. verticllioides isolates gave the expected fragment with 183 bp in size. Therefore, this study demonstrated that F. verticllioides isolates genetically have a potential for fumonisin-production. It also showed that the PCR-based technique can be used for the identification, distinction and detection of the Fusarium species.

Turnip mosaic virus is a member of the genus Potyvirus in the family Potyviridae and has the broadest host range in the family. In order to detect and characterize local isolates of TuMV, 175 saffron samples were collected from Birjand, Khosf and Ghaen in South Khorasan between October and November 2016. Infections with TuMV were detected by ELISA in 10. 85 percent of samples. Total RNA was extracted and subjected to RT-PCR with the virus coat protein (CP) specific primers. As a result, full-length CP gene (980 bp) was amplified from nine samples and sequenced. Phylogenetic analysis of these isolates and 30 GenBank TuMV isolates showed that six Iranian isolates fell in Asian BR group with other isolates from Iran, China and Turkey. Three Iranian isolates fell in World B group with the isolates from Canada and new Zealand. Homology matrix showed the highest similarity between SKK10 and IRNTT3 and the lowest between SKK10and AB093598 from Italy (98. 96 and 87. 2%, respectively). The phylogenetic analysis showed that TuMV isolates from saffron plant in Iran were classified in different groups; therefore, they may have derived from different ancestors. This is the first investigation of TuMV on saffron in Iran.

The most important pest of weeping willow trees in landscape of Tehran are wood borers that cause damage to branches or tree. In this research, integrated pest management of the metallic wood-boring beetle, Melanophila picta Pall. (Col., Buprestidae) on Babylon weeping willow trees in the campus of Shahed University campus was studied during year 2016. A Randomized Complete Block Designs (RCBD) was adopted to evaluate effect of seven treatments chemical, mechanical, cultural and three replications, in regarding of number of ooze out of the tree trunk (in September) and the death rate of the trees (during autumn). Based on adult emergence holes, first emergence of the adult insects occured in early May and at during May to late May it reached to peak. The effect of different treatments on the wood borers showed a significant difference between them. Comparison of means showed that spraying the trunks and branches with 1500 ppm Chlorpyriphos plus 2000 ppm Volk oil, applying of super absorbent polymer, combined treatment (spraying and super absorbent) and repellent getaway were in one group with no tree was died. Mortality followed by control with more than 18 percent mortality. Also, results showed that getaway repellent, mesh fabric and Vienna humic acid fertilizer were similar in preventing oviposition of poplar borer beetle while oozing was significantly higher in control. So, spraying the trunk at adult emergence (June) or using repellent substances or avoiding water stress of the plant, have effective role in preventing damage.

In this study, two grape orchards infected by vine cicada were selected in Baba-raees and Mishen villages of Malayer, with different soil structure and an uninfected one in Malayer station. The biology of the pest studied by encaging 15 grape trees in the uninfected orchard and releasing five mature male and females of the vine cicada in each cage. The developmental stages of the insect thus onset and the peak of emerging nymphs, the trends of population fluctuation and infection rate were determined observing exuviae and emerging holes. The adult longevity was 11 days and the hatching duration of eggs was about one month. The adult cicadas flied late June to late August and the nymphs were emerged from the soil late August. Compared to the orchards with relatively heavy texture, the severity of infection was higher in orchards with relatively light texture soil. It was found that the peak of the nymph emergence was happened when both air and soil temperatures at the depth of 30 cm, reached to maximum of, 34° C. Moreover, the onset and peak of the nymph emergence Occurred when 408 and 1342 Growth Degree Day (GDD) was accumulated for vine trees respectively. In addition, the peak had a negative and a positive correlation with relative humidity and evaporation, respectively. Furthermore, the rate of egg parasitism was 1. 16% and 0. 78% in Baba-raees and Mishen respectively.

The common green lacewing, Chrysoperla carnea (Stephens) is known as an important biological control agent. In this study, the effects of field recommended concentrations of emamectin benzoate and spinosad were evaluated on the biological parameters of C. carnea. Bioassay tests were done on second instar larvae of green lacewing by contact residue method at 26± 1 C  , 70± 5% RH and a photoperiod of 16: 8 h. (L: D) The results showed that the tested insecticides at recommended field concentration had negligible toxicity on second instar larvae of green lacewing and according to IOBC standard method, emamectin benzoate and spinosad were classified as harmless. Fifty and 240 mg a. i. /l of emametin benzoate and spinosad (twice recommended field concentration) increased larval duration by 7. 7 and 15. 5 % and pupal duration by 7. 6 and 11. 4 % compared with control, respectively. These insecticides increased larval mortality rate significantly compared with control but they did not affect pupal mortality rate. Fecundity, fertility and adult longevity were not affected significantly by tested insecticides compared with control. Results showed that tested insecticides had low adverse effects on the green lacewing. Therefore, the tested insecticides and green lacewing as biological control agent can be used in integrated pest management programs.

Fusarium wilt caused by Fuarium oxysporum f. sp. melonis is one of the most important disease of melon in Iran and some countries around the world. The purpose of this study was to investigatethe genetic diversity of this pathogen in Iran. In this study, 50 isolates of F. oxysporum were collected from melon plants(cantaloupe and muskmelon) with wilt and yellowing symptomsacross Iran. The isolates were identified using morphological criteria and their pathogenicity was confirmed. Genetic diversity of the isolates was then determined by rep-PCR technique using ERIC and BOX primers and NTSYS software. The results of pathogenicity testshowed that there were significant differences at the 1% level probability among the isolates in disease incidence, disease severity and plant growth parameres (fresh weight of roots and shoots). The highest disease incidence was observed in plants inoculated with isolates Race1-2, 605, 606and 609and the highest disease severity was induced by isolates 607, H2, F-186-4 and F-186-6. Isolates F-186-1, F-66-4, F-186-4and H9had the highest and isolates F-186-6, F-66-4 and 501 had lowest effects on decrease of fresh weight of roots and shoots, respectively. Genetic diversity test divided the isolates into 4 groups A, B, C and D in 63% similarity level. This study showed that the genetic diversity among the isolates of F. oxysporum f. sp. melonis is high in Iran. There was no correlation among Rep groups, pathogenicity and geographic distribution of the isolates.

The predatory mite, Neoseiulus californicus preys on phytophagous mites and small insect pests. Different methods were investigated for studying of mass rearing methods of this predatory mite. We used different host plants (lima bean leaves, strawberry leaves, mulberry leaves, cucumber leaves) and artificial plates as arena and different diets (Tetranychus urticae Koch eggs, Tyrophagus putrescentiae (Schrank) nymphs and adults, and Anagasta kuehniella (Zeller) eggs), plant pollens (walnut pollen, sun flower pollen, bee pollen, corn pollen and date pollen). In each rearing container, 15 female predatory on exciseted sponge used. The number of predatory mites were counted after 5, 10 and 14 days. In another test, we investigated the survival and fecundity rate with removeing the eggs of predatory mite in each container. The best choice for mass rearing of this predatory mite is agar beds with feeding on Tyrophagus mite. The longevity (18. 50 days) and fecundity (34. 10 eggs per female) of the predatory mite on agar were more than other treatments (P<0. 05). The plastic arena prepared appropriate condition for this predatory mite. The best choice for mass rearing between the tested pollens were walnut and date pollen because of their more nutritious compounds. The date pollen is the most economic. The nymphs and adults of Tyrophagus mite were suitable. Using of artificial materials such as agar and plant pollens for mass rearing of this predatory mite could facilitate the way for control of key pests.

Tomato leafminer moth (TLM), Tuta absoluta (Meyrick), is a serious new pest in field and greenhouse grown tomatoes in Iran. Chemical control is an important component of this insect pest management in outbreak conditions. This study investigates the effectiveness of five new insecticides against TLM. Bioassays were conducted on 3rd instar larvae of TLM in laboratory conditions. Also, efficacy of insecticides was evaluated in a Completely Randomized Design (CRD) with six treatments and three replications in the greenhouse. The treatments included thiocyclam (Evisect® SP 50%) with concentration of 1gl-1, flubendiamide (Takumi® WG 20%, 0. 2 gl-1), chlorantraniliprole + abamectin (Voliam Targo® SC 6. 3%, 0. 8 g l-1), emamectin benzoate (Proclaim® SG 5% 0. 3 g l-1), Spinosad (Tracer® SC 24%, 0. 25 g l-1) and control (water spray). The bioassay results showed that chlorantraniliprole + abamectin (LC50=0. 01 mg ai l-1) and thiocyclam (LC50=29. 9 mg ai l-1) had the highest and the lowest toxicity on the TLM larvae, respectively. Also, the greenhouse results showed that all of the insecticides had acceptable efficacy at the tested concentrations on the TLM larvae. Voliam Targo® and Takumi® had the best efficacies against TLM on 10 and 13 days after treatment and followed by the rest insecticides. All tested insecticides had a high potential toxicity against TLM.

Due to the importance of white button mushroom as a source of food and protein, the identification and control of its diseases are taken into consideration in the world. In Ardabil province, there are several mushroom production units. In this research, infected samples were collected from Ardabil, Namin, Sarein, Meshginshahr and Pars-Abad mushroom farms. After isolation and purification of fungicolous fungi from infected mushrooms and casing soil, macroscopic and microscopic features including colony characteristics on MEA/PDA and conidium/conidiophore size and shape were used for tentative-identification of isolates using valid keys. The results were confirmed by sequencing of ITS-rDNA region. In this study, among 72 fungal isolates, Lecanicillium fungicola, causal agent of dry buble, Trichoderma harizianum and T. virense causal agents of green mold, Mycogone perniciosa causal agent of wet bubble, and Cladobotrium mycophilum causal agent of cobweb were identified with 49, 18, 14, 14 and 5% frequency, respectively. This is the first study on mycopathogens of button mushroom in Ardabil province. The results may help to prevent and control the mycopathogenic fungi in button mushroom production units after additional research.

Penicillium digitatum, the causal agent of citrus green mold, is one of the most important pathogens among citrus fruit rot agents. Unfortunately, the continuous application of chemical pesticides have serious effects on human health and environment. As well as development of resistance is a latest against their resistance to chemical pesticide. Today, research on bio-pesticides using microbial antagonists and natural plant products has become more important as viable alternatives to control postharvest diseases. In this research, some wide spread endemic plant spears were collected from North of Iran and their potential as natural bio-pesticide were evaluated. Metabolic extracts of these plants were tested on PDA medium in vitro and on citrus fruits in vivo for their efficacy to control P. digitatum when applied as disc diffusion method and soaking in plant extract suspension respectively. Results showed some plant extract produce inhibition zone around paper disc In vitro test, but in vivo test, only extract of Phytolacca americana has significant effect and inhibited spore production by Penicillium sp. Eleven Components were identified from Pytolea American extranets using eleven Chromatography by Hexane, Diethyl ether and Methanol solvents, an non-polar, semi-polar and polar solvent, respectively. And purified using thin layer Chromatography (TLC). The antifungal effects of each 11 components on P. digitatum showed only component were extracted with methanol polar solvent have the most antifungal properties.

Sclerotinia basal stem and stem rot, caused by Sclerotinia sclerotiorum and S. minor, is one of the most devastating diseases of sunflower. The use of resistant cultivars is considered as the most important method to control this disease; however, the employment and development of these cultivars require information on the aggressiveness of the pathogen in the region and interaction of fungal isolates with host genotypes. In this research, aggressiveness of 15 S. sclerotiorum and 14 S. minor isolates collected from sunflower fields in different regions of West Azarbaijan province was initially studied on the cultivar Farrokh. Aggressiveness of S. sclerotiorum isolates ranged from low to high, however, low aggressiveness diversity was observed among S. minor isolates and most of them were highly aggressive. Interactions between three isolates of each fungal species and 40 sunflower lines were then evaluated in controlled condition. Isolate-specific resistances to the pathogens were identified in some studied lines and the two lines, 15031 and ENSAT-699, were resistant to the three isolates of S. minor. Among the resistant lines identified in this study, the Iranian line ‘ 110’ with resistance to two isolates of each of the pathogens and with low mean infection (79. 44 ) was among the most resistant lines. The new sources of resistance identified in this study could be used in sunflower breeding programs to develop cultivars with broad spectrum resistance to both pathogens.

Leaf stripe disease (LSD) of grapevine, which was previously known as esca complex disease, is one of the most important and destructive trunk diseases of grapevines. Phaeoacremonium minimum is the principle hyphomycete associated with disease. Chemical control of LSD has proven difficult, meanwhile, application of biological control agents for disease management have been promising. The aim of present study was to evaluate inhibitory potentiol of three Trichoderma species sincluding one commercial product (Trichoderma harzianum T22) and two endophytic isolates, T. longibrachiatum and T. brevicompactum, against four isolates of Pm. minimum with opposite mating type (two MAT1-1 and two MAT1-2 isolates) using dual culture, volatile and non-volatile metabolite assays. The results of this study showed that all three species of the antagonist had significant inhibitory effect on the growth of Pm. minimum, in comparison to the control. In dual culture assay, T. harzianum T22 showed the highest potential in the inhibition of the Pm. minimum growth, with 76. 53 percent growth inhibition, in comparison to the two other antagonists. In volatile metabolites assay, significant differences were observed among the antagonists in growth inhibition of the Pm. minimum. In non-volatile compounds assay, T. brevicompactum with 75. 46 percent growth inhibition of pathogen, showed the highest control potential in comparison with the other two species. Non-volatile compounds of T. longibrachiatum and T. harzianum T22 showed 46. 93 and 17. 67 percent inhibition on colony growth, respectively. Evaluation of the inhibitory effects of these antagonists on the opposite mating types of Pm. minimum showed that volatile compounds of T. longibrachiatum were more effective on MAT1-1 (48. 74% growth inhibition) compared to MAT1-2 (35. 10 growth inhibition). Overall, the results of this study reveal T. brevicompactum as an effective antagonist against Pm. minimum; hence, further evaluation of its biocontrol properties and efficacy in disease control under greenhouse and field condition remain to be studied.