PLANT PROTECTION JOURNAL
Year:2012 | Volume:4 | Issue:1 (13)|Papers Count:10

The Asian citrus psyllid, Diaphorina citri Kuwayama, is a vector of Candidatus Liberibacter asiaticus that causes citrus greening disease. The vector population has increased drastically in our country, in recent years. Entomopathogenic fungi are among those agents which might have the potential to suppress its population. To study the effects of these agents on adult psyllids and the relationship between fungus-sprayed area and mortality, two isolates, DEMI 002 (Metarrhizium anisopliae) and DEPI 002 (Isaria tenuipes) were investigated in the laboratory. Four leaf sections were placed together in a Petri dish and one to four of them were sprayed by the fungal suspensions at a concentration of 7×105 spores/ml and two adult psyllids were released into Petri dishes. Five days after treatment, ‘DEMI 002’ and ‘DEPI 002’ caused 71% and 29% mortality, respectively. DEMI 002, an isolate of Metarrhizium anisopliae, was significantly more effective than DEPI 002 (Isaria tenuipes). However, there was no statistical difference between different leaf area coverage on mortality, showing the horizontal transfer of the fungi among the psyllids. Application of entomopathogenic fungi at low quantities combined with other control techniques is an appropriate option in an IPM approach against D. citri.

The cabbage white butterfly, Pieris rapae (Linnaeus, 1758) (Lep.: Pieridae) is one of the most important pests of Cruciferous or Brassicaceae family plants in regions of Shahriar, Kahrizak and Sahr’e Ray and every year its damage can be seen on the leaves of these plants. In order to study the seasonal population fluctuation of P. rapae, One hectare cauliflower field in the middle of a large field was randomly selected in five regions of cauliflower fields in south of Tehran were chosen and sampled every 10 days. Each plant was presumed as a sampling unit and sample size was determined as 20 host plants and all eggs, larvae and pupa on the host plant were recorded. Results of this study showed that Jahanabad and Shahed fields had the highest egg density (18.91±5.60) and the lowest egg density (16.53±4.04) was seen in the Playin field during season. In the Shahed field, highest egg density occurred in June 19 and the lowest egg density was seen on October 25. In the Playin field, the highest and lowest egg density was seen on September 29 and June 19, respectively. In the Jahanabad field the highest (2.99±0.66) and lowest (0.41±0.10) larval density was occurred during the season among different regions. Highest density was observed in the Jahanabad field during the harvest time on October 25 and the lowest larval density was seen on June 19. The highest and lowest larval density was seen in the field of Playin on 25rd October and 19th June, respectively. Kahrizak (0.87±0.16) and Playin (0.19±0.05) fields had the highest and lowest pupal density in different regions during the season. In the field of Kahrizak, highest pupal density was occurred on 25rd October and in the playin field, the lowest pupal density was seen on 19th June. In the Playin field, highest density of pupae was occurred on 14th October and 25rd October and the lowest density of pupae was observed on 19th June and 2th July, respectively. The results showed that number of larval and pupal stages based on units density, between all experimental regions and Shahed university station had not significant difference.

In this research, biotic index and water quality of Khong river of Sepidan region in Fars province was estimated by using aquatic insect fauna during 2009-2010. The aquatic insect fauna were collected from different places of the river and identified in family level. Then the water quality was estimated by Hilssenhoff biotic index formula. A total of 39 families from 7 orders of insects (Trichoptera, Hemiptera, Odonata, Plecoptera, Diptera, Ephemeroptera and Coleoptera) were collected and identified from 4station of the river. In this research, biotic index of the Khong River was estimated 3.79 and quality was excellent (Slight level of pollution by organic material).

Codling moth, Cydia pomonell, is the key pest of apple orchards at Khanehzenyan, Shiraz, Fars, Iran. To determine the best application time of spraying via counting the number of trapped moths and recording the effective daily temperature during 2009-2011, pheromone traps used at the height of 1.5 m from the ground level with distance between traps of 85-100 m. The data was analyzed using Excel software. According to the results, the number of pest generations and spraying time were determined. The results indicated that C. pomonella had two complete and one partial or incomplete generation at Khanezenyan. The best time for chemical control of C. pomonella was coincident with the time of appearance of the first age larva and accumulation of 175 degree-days. The required sums of temperatures for completion of one generation of C. pomonella were 766.5 and 770 degree-days for the years 2009 and 2011 respectively. Therefore, by this way we can reduce the irregular uses of chemical pesticides and environmental pollutions.

Tomato pests, such as tomato fruitworm, Helicoverpa armigera Hunber (Hym.Eurytomidae), cause high reduction in tomato production, but no sampling program for population estimate and management of them has been developed. Spatial distribution of immature stages of the tomato Fruit-worm was determined by fitting data to either taylor’s, iwao’s, mean_variance ratio, k and morisita calculating dispersion indices, during 2008 and 2009 growing seasons in tomato fields of Gorgan, Spatial distribution immature (egg and larvae) is a random. Based on R2 and p-values of regression analysis, for most of the natural enemy groups, Taylor’s power law generally provided a more adequate description of variance/mean relationships than Iwao’s patchiness regression model. The median part of plant were fitted most value of Taylor’s b index. Percentage fit of immature stages the dispersion more random ratio bionominal value of morisita, k and mean-variance.

Considering the abundant application of pesticides, the subject of pesticides and their exceeded residues on harvested crops is important issue in agriculture. For this purpose, comprehensive and several studies on agricultural products should be done to prevent of entering of contaminated samples in using cycle. In this study, among 29 fruits and vegetable markets in Karaj, 10 of them in different parts of the city were considered, and 25 samples were randomly prepared for each specimen, weighing 2 kg. Samples in laboratory were extracted by using Solid Phase Extraction (SPE) and with the help of N method were concentrated and extracts were injected into High Performance Liquid Chromatograph (HPLC), Gas Chromatograph (GC/NPD), GC/Mass Spectrometer (GC/MS) devices for measuring the residue. Obtained data were compared with WHO/FAO and national Maximum Residue Limit (MRL) codex by T-test. The results showed that for chlorpyrifor 6 and 20 numbers (24 and 80%) of samples based on WHO/FAO and MRL codex respective, and for deltamethrin 14 numbers (56%) of samples based on WHO/FAO codex have had exceeded contamination of insectides.

The Ephestia kuehniella is one of the important pest of storage Date. This research was conducted to evaluating the efficiency the suitable Iranian isolate of Fungus Beauveria bassiana for the microbial control the flour moth on the Sayer date cultivar. The larvae were treated by 5 doses of fungi including 104, 5×104, 105, 5×105 and 106 spores/ml to determine the lethal power, with dropping method. Data were calculated by using Log-Probit analysis methods. Results showed that the highest and lowest LC50 were for pupa and egg equivalent to 1.76×104 and 3.49×103 spores/ml respectively. The lowest and highest LT50 were assessed for pupa and egg equivalent to 3.67 and 3.38 days respectively. The research results of in the laboratory phase as the first step of feasibility of fungus application in microbial control showed that fungal pathogen had high potential for application on control of flour moth in date.

A survey was conducted to detect the distribution of tomato (yellow) leaf curl disease in tomato fileds of Fars province including Lamerd, Lar, Farashband, Kazeroon, Mamasani, Shiraz, Saadat Shahr, and Abadeh region during winter, spring and summer of 2012. Suspected samples that showed severe leaf curl associate with stunting and yellowing around the leaves were collected. After DNA extraction, samples were tested with specific primers of Abadeh isolate and degenerate primers of begomoviruses using polymerase chain reaction (PCR). The results showed that Lamerd, Lar, Saadat shahr, Abadeh and Mamasani regions are infected and distribution map of TYLCV was drowning in Fars Province.

During summer 2012, fifty-seven cucurbits samples were collected in order to determine their viral diseases in cucurbits fields of Shiraz and suburbs (Kaftarak, Baboonak, Tafihan, Daryan, Bidzard, Zafar abad, Kooshk-e- bidak, Sadra and Dokoohad). Samples were examined by using three local antisera, CMV, ZYMV, SqMVby indirect ELISA. ELISA results were confirmed by RT-PCR with specific primer pairs for each virus. Results showed that the most important damaging viruses in these zones were Cucumber mosaic virus with 49.1% with showed yellowing, chlorosis and leaves deformation, Zucchini yellow mosaic virus with 35.1% infection induced mottling, sever shoestring and blusters on leaf surface and Squash mosaic virus with 29.8% incidence with leaf yellowing and mottling on cantaloupe and squash respectively. Furthermore, in some places mixed infections to sort of viruses were seen. Nine samples were infected by CMV, ZYMV and SqMV (15.8%) showing mottling and large blusters with sever shoestring and leaf deformation. Seven samples were infected by CMV and ZYMV (12.3 %) with partially mottling and shoestring, five samples by CMV and SqMV (8.7%) in which small green blusters on leaves were seen and finally one sample to SqMV and ZYMV (1.7%).

Fusarium wilt (Fusarium oxysporum f.sp. tuberose) is a major disease of potato, causing considerable damage and losses. The sources of genetically resistant are the best method of controlling the disease. In this study, the reactions of 18 potato cultivars were assessed to F. o f.sp. tuberosi in a factorial design with four replicates, in the greenhouse. Plants were inoculated (15 cm height) twice with three isolates of the pathogen by root inoculation (100 ml of 4×105 spore/ ml). Tento thirty days after inoculation cultivars were evaluated according to the symptoms disease index, the lengths of necrosis in vascular tissues, stem height and roots lengths There was a significant difference between parameters (P=0.01). Necrosis lengths had maximum correlation in vascular tissues (r=0.86), then root lengths (r=0.75), symptom disease index scale (r=0.73), and stem heights (r=0.69). There was a significant difference between cultivars (P=0.01). According to lengths of necrosis in vascular tissues cultivars divided in five groups, Gorican, Tiuva, Diamont, Marfona, Baraka, Aola and Moren were very susceptible and Olva, Folva and Alva were tolerant.