نشریه تحقیقات نوین در گیاه پزشکی
سال سوم شماره 4 (پیاپی 12، زمستان 1390)

Seasonal parasitism of Phyllocnistis citrella Stainton (Citrus leafminer) were investigated weekly during June 2010–September 2011 in two citrus orchards in Shiraz. In orchard 1 Parasitoids were collected from larvae and pupae stage of citrus leaf miner: Pediobius pyrgo Walker, Pediobius saulius Walker, Pnigalio soemius Walker. Moreover, Closteroceros formosa Westwood was observed in orchard 2. The most percentage parasitism was related to species P.soemius with 1.69% in orchard 1 and C. formosa with 26.32% in orchard 2. In orchards (1) and (2) the most percentage parasitism was in November 2010 with 2.88% and in January 2010 with 50.01% respectively.

Fruit flies (Diptera: Tephrtidae) is the most important pest causing damage to citrus fruit trees in the north of Iran. Biology of C. capitata was investigated on five mandarin cultivars under laboratory condition at temperature 27±1 OC, 70±5 RH and photo period 14L: 10D in control unit of Iran citrus research institute greenhouse in 2011. The result indicated that the mean developmental time of eggs under laboratory conditions on Page, Celementin, Onsho, Unesi and Yashar cultivars was 2.5±0.15, 1.8±0.2, 1.3±0.2, 2.4±0.18 and 2.7±0.12 days, respectively. The mean of larval period ranged from 9.8±0.2 days on Unesi to 12±0.22 days on page. Also, the experiments showed that there were no significant differences between pupal duration and pupae weight on mandarin cultivars. The mean developmental time for entire immature stages on Page, Celementin, Onsho, Unesi and Yashar was 27±0.52, 24.1±0.65, 22±0.57 25±0.65 and 26.5±0.47 days, respectively.

Family of Entomobryidae belongs to order of Collembola (springtails). The members of this family distinguish from other family by slender body, long hairs body, scales one body and lengthier fourth abdomen segment than third one. For study this family in during 2011- 2012, the sampling of soil and leaf composts, from different areas of Choram (kohgiloyeh and Boyer Ahmad province) and Collembola were extracted by heat in Berlise funnel. Microscopic slide were provided by Hoyer medium. In sum, five species from three different genus were collected and described which comprised one species belong to Willowsia genus, two species belong to Entomobrya genus, two species belong to Lepidocyrtus genus. The species are new for Iran fauna.

The Colorado potato beetle, Leptinotarsa decemlineata (Say), is a serious pest of potato, Solanum tuberosum L. worldwidely. One of the methods used for controlling of it is deployment of resistant cultivars. Field experiments were conducted to evaluate the antixenosis resistance in 33 potato cultivars to this pest during 2007 - 2009. Research method in 2007 was similar to 2008 and was different from 2009. In a field choice test, the numbers of attracted beetles to the cultivars were determined as antixenosis index. Numbers of attracted beetles to the cultivars and numbers of egg masses on them were used as antixenosis indices during 2009. Cluster analysis of cultivars was performed with MINITAB15 statistical software using UPGMA procedure based on Euclidean distance. Combined analysis of variance of choice test data in 2007 and 2008 showed that with point of settled adult beetles on the studied cultivars, significant difference was observed between experimental years, blocks, times of counting, cultivars and reciprocal effect of cultivar × year (P < 0.0001). Mean comparison showed that cultivars Bright, Delikat, Nicola, Sinja, Carlita and Cardinal in 2007 and Cardinal, Carlita, Sinja, Elles and Romina in 2008 had the highest antixenosis resistance with the least settled adult beetles on them. Cluster analysis showed that in two first years, cultivars Cardinal, Carlita, Sinja, Bright, Raja, Nicola, Romina, Santana, Elles, Fianna and Satina with the least attracted beetles were resistance group in antixenosis index. Also, cluster analysis based on the number of attracted beetles to the cultivars and number of egg masses on the cultivars showed that cultivars Bridjet, Baltica, Cardinal, Nicola, Raja, Bright, Delikat, Carlita, Provento, Cosima, Armada, Elles and Beluga were placed in one group and had the highest antixenosis effects compared to others cultivars in 2009. Mean comparison showed that cultivars Cardinal, Carlita and Bridjet had the highest antixenosis resistance with the least settled adult beetles on them in three experimental years.

Carob moth, Ectomyelois ceratoniae (Zeller) (Lep.: Pyralidae) is the most important pest of pomegranate fruit in Iran. In the present study, the effect of applying timing of covering and different types of covering on infestation rate to carob moth were tested in Neyriz region (Fars province) from May to October in 2012. For this purpose, 45 trees of a orchards were selected randomly, treatments were included: crown flower covering, crown fruit covering, complete flower covering and complete fruit covering. There were signification differences between treat ments related to to pest infestation. The result showed that the mean infestation rates were 25.3% and 9.6% for control and complete covering of flower with fabric net in the first decade of May, respectively, so complete covering flower with fabric net in the first decade of May can reduce fruit damage by 62%. Highest percentage of infestation were recorded for using fabric net on fruit crowns (14.44%) and the lowest were observed for using fabric net on pomegranate flowers (9.66%). Comparison of flower and fruit drop, fruit cracking and infestation between treatments indicated that complete covering of flowers with fabric net in the first decade of May can be recommended for reduction of E.ceratoniae infestation. Therefore, the results revealed that the using fabric net on pomegranate flowers can be recommended in this region.

Rhizoctonia canker, also known as stem canker and black scurf of potato, Rhizoctonia solani Kuhn, causing serious economic losses by canker on under ground stem, roots, stolens, blanding of tubers and black scurf on potato surfacee in Isfahan. In this manscript, the effects of green chitting and or disinfection of potato seed tubers and soil were considered on this disease in the fields. The laboratory trails on R. solani isolates indicated that, almost all the sclerotinia are pathogenic. The seed tubers of four potato cultivars were selected and kept under room temperature along with normal light and high humidity for two months. Then, they were sown in the highly infested soil to the disease. The results indicated that the green chittings reduced Rhizoctonia stem canker severity effectively. In comparison to the above experiments, the fungicide screening, Rovral in the form of seed, soil and simultaneous seed and soil applications were carried out in the same fields. The results showed that the stem canker severity was reduced effectively compared to chittings and that of control. Increased growth response was observed in only green chitted potato seed tubers compared to other treatments.

Green and Blue molds are the major postharvest disease of citrus fruit that caused by Penicillium digitatum and p.italicum those responsible for about 30% of losses in citrus crop per year. In common methods, these wound pathogens have been controlled by using synthetic fungicides such as Imazalil, benomil or thiabendazole. Concerns about their impact on human health and the environment and the rise of fungicide-resistant biotypes, biological control proposed as a suitable replace. In this research, for biological control on these pathogens, epiphytic microorganism isolated from fruit surfaces that collected from the citrus orchards in the North of Iran. Initial evaluation for Biological Control potential by these microorganism were done based on pathogen inhibition zone in laboratory conditions. 65 isolates of yeast and bacteria and 30 isolates of mold show potential for Biological Control on these molds. In next stage, fruit were wounded to a 2 mm depth of four equidistant points and microbial treatment were inoculated to each point bacterial and yeast suspension of 1×108 cell/ml concentration 24 h before pathogen spore inoculation (1×104 spore/ml) and in hold 15 c for one week. Results of microbial treatment compared with control based on appearance and severity of incidence. Biochemical test for identification of Biological Control isolates showed 3 isolates of Pseudomonas syringae, 2 isolates of Pantoea agglomerans and 1 isolates of Candida famata. Inhibitory mechanism of Biological Control showed evidence in production of volatile compounds and extracellular metabolites from P. syringae and extracellular metabolites from C. famata those have antifungal effect on P. digitatum and P. italicum.