فصلنامه فن آوری های نوین کشاورزی
سال چهارم شماره 2 (1389)

Alfalfa weevil, Hypera postica and Alfalfa root weevil, Sitona discoideus, are native insects of Alfalfa (Medicago sativa), causing damage up to ~100 and 60 percent respectively. Microctonus aethiopoides Loan is a solitary endoparasite of adult weevils of the genera Hypera and Sitona. Biology and potential for biological control were investigated in laboratory and field trials in Qazvin, Iran, from 2009 to 2010. In the laboratory experiment (26°C, 70% R.H.), duration of development from egg to pupa and pupa for male were 14.73 ± 0.34 and 6.03 ± 0.11 daysresp. And also these parameters were for female 15.16 ± 0.19 and 7.125 ± 0.23 daysresp.Parasitism percent reached 39% and 1% for H.postica and S.discoideus resp.The sex ratio (M: F) was different in first (emerged from overwintering hosts) (0:1) and second generation (1:1.2).The number of wasp adults that emerged per parasitized beetle was one. This parasitoid has two generation per year. First emergence of 1st and 2nd adult parasitoids recorded at early of April and October resp.In the field, the populations of the 1st generation adults of the parasite were synchronized well with those of the overwintered weevils, resulting in parasitism of 15-33% for alfalfa weevil. The 2nd generation of the adult parasites and the summer adult weevils overlapped and parasitism of the diapausing hosts (H.postica and S.discoideus) were 9-15% and 0.05-0.7% resp.

Olive fruit fly Bactrocera (Dacus) oleae is one of the injurious pests of olive which has caused considerable damage to olive orchards in recent years. Larval feeding on olive fruit induce fruit fall and decline the qualitative and quantitative parameters of olive oil.. Moreover, exit hole of the larvae provides way for additional fungal infections leading to fruit deformation and loss of marketing values. Different cultivars show different reactions to pest damage which can be used in integrated pest management. This research was carried out during 2006 using olive collections of Roudbar, Tarom and Loshan research stations located in Gilan, Zanjan and Qazvin provinces respectivelly. Sampling from fruits was started during stone hardening and continued untill harvest time and 20–50 fruits, were collected in each replication and examined carefully visually and under binocular microscope in laboratory. Over all results showed that native cultivar of “Roughani” differed significantly from the other cultivars, including three imported cultivars of: “Konservalia”, “Arbequin”, “Leccino” and two native cultivars land races of: ”Zard’ and “Mary” and had less of less susceptibility to olive fruit fly.

Biocontrol of plant disease agents in order to decrease the hazardous impacts of chemical pesticide application including problems of public health, environmental pollution, toxic effect on non-target organisms and causing resistance disease agents is a priority. In this study, crude methanolic extracts of 27 plant species were extracted and screened for antifungal activity against three economically important phytopathogenic fungi, Rhizoctonia solani, Phytophthora drechsleri and Pythium aphanidermatum. Because of insufficient material, only 18 out of 27 plant species were tested against Fusarium oxysporum and Cochliobolus sativus. Bioassay was performed based on paper disc diffusion method with four replications. The results showed that 11 out of 27 plant species (about 37%) inhibited mycelia growth of at least one of the studied tested fungi. The mycelia growth of R.solani, P. drechsleri and P. aphanidermatum were inhibited by 10, 9 and 9 plant species, respectively. Among 18 tested plant species, four species suppressed the growth of Cochliobolus sativus. The other fungi, F. Oxysporum was measureably inhibited by only one plant species, Syzygium aromaticum. These results indicated that R.solani and F. Oxysporum are the most sensitive and resistant fungi to plant extracts, respectively. The antifungal activity of Syzygium aromaticum, Myristica fragrans, Ferula assa- foetida, Artemisia sieberi, Allium ascalonicom, Prangos ferulacea and Solanum nigrum against all of the tested fungi represent their broad fugistatic specterum. It was concluded that plant extracts have a remarkable potential as biocontrol agents against phytopathogenic fungi.

The rice striped borer, Chilo supressalis walker is the most important pest insects of the rice in the most of its growing areas throughout the world. In order to control rice striped borer, among new controlling methods, ovoparasitoid wasps of the family Trichogrammatidae considered as an important biological control agent. The effect of different rice cultivars as the first link in food chain on reproductive periods and reproductive parameters of Trichogramma embryophagum as the 3rd link in food chain was studied. Experiment was conducted at temperature 27±1°C, 50±10% RH and a photoperiod of 16:8 (L:D) h. Four rice cultivars including two early maturity cultivars namely, Tarom Mahali and Tarom and two late maturity cultivars namely, Fajr and Neda were selected for experiment. The rice stem borer was reared on rice cultivars as the host of parasitoid wasps. Rice stem borer eggs were transferred to separated test tubes per each newly emerged female wasp. For each rice cultivar, 100 female wasps were considered per each rice cultivars. Developmental period, reproductive periods and reproductive parameters of the egg parasitoid wasps were determined based on recorded data. Results showed that the developmental period of T. embryophagum in all of examined rice cultivars is 9 days. In addition, all of the emerged wasps start to egg lying from the first day of the emergence; therefore, pre-oviposition period was zero. Among rice cultivars, wasp post-oviposition period, oviposition period and adult life span had not statistically significant difference (P>0.01, f=2.36, df=3). Values of the other evaluated reproduction parameters including gross fecundity rate, gross fertility rate, net fecundity rate, net fertility rate, gross hatch rate, mean egg per day and finally mean fertile egg per day were higher in late maturity rice cultivars than early maturity rice cultivars. Between late maturity rice cultivars, Neda was higher than Fajr considering all of the mentioned above factors.

To study the role of Phytophthora species associated with greenhouse tomato root and crown rot, diseased sampled were collected in Kohgiluyeh and Boyerahmad province. Pieces of infected root and crown of tomato were washed with tap water blotted dry and plated on CMA supplemented with delvocid(10ppm pimarcin), ampicillin(250ppm), rifampicin (10ppm) and PCNB (150ppm). 34 isolates recoverd from various parts of the Kohgiluyeh and Boyerahmad province. Colonies on the selective medium based on morphological characters produced and temperature requirement, the pathogen were identified as Phytophthora capsici and P. cryptogea. 15 isolates were identified as P. capsici and 19 isolates were identified as P. cryptogea.The reaction of crown and root of 3-week-old greenhouse tomato cultivars, Karina, Manisha, Aget, Cluster5, GH11 and GH12 to virulent isolates of P. capsici and P. cryptogea was evaluated under greenhouse conditions. The inoculum was obtained on vermiculite-hemp seed extract and positioned around either crown or root systems. Percent dead seedlings and crown and root colonization were evaluated. Comparative percent dead seedlings and crown and root colonization showed that Karina and GH12 cultivars were the most susceptible and the least susceptible in reaction to P.capsici and P. cryptogea. Resistance tomato cultivars in reaction to Phytophthora capsici were Karina, Aget, Manisha, Cluster5, GH11 and GH12 and in reaction to Phytophthora cryptogea were Karina, Manisha, Cluster5, Aget, GH11 and GH12.

Onion (Allium cepa L.) is one of the most important vegetables cultivated in Zanjan province. Fungal diseases, pests and weeds cause considerable damage to quantity and quality of this crop. The present study, addresses identification important fungal diseases of onion, their, distribution and their economical importance in fields and storerooms. Randomly collected leaf and bulb samples, carrying disease symptoms from 44 fields, and 10 storerooms, were transferred to zanjan plant disease laboratory to determine fungal agents and subsequently for possible pathogenicity test if it was applicable. The percentage of infection in the fields and the percentage of infected fields for each fungal pathogen were estimated by counting the number of infected plants and number of infected fields, respectively. In addition, post harvest diseases of onion was investigated by collecting samples from storerooms, isolating of pathogens and estimating the percentage of infection. Results showed that red root disease caused by Pyrenochaeta terrestris, and basal rot caused by Fusarium oxysporum were the most frequent diseases of onion in the fields with 9.9 and 2.8 percent infection, respectively. Post harvest diseases of onion, however, caused mainly by Fusarium oxysporum and Botrytis sp and occurred in a lesser extend in storerooms. The overall loss was estimated up to 22.7 percent by these fungal diseases.

Cucumber mosaic virus, the type member of the genus Comovirus (family Bromoviridae), is one of the most important viruses causing damage to cucurbit crops worldwide. During 2008-2009, a survey was carried out in major olive growing areas of Zanjan province. About 342 samples showing symptoms of viral infections (mosaic, yellowing, leaf deformation) were collected. All samples were subjected to serological assay using double antibody sandwich-ELISA (DAS-ELISA). Four isolates were selected from different fields to determine the biological properties of the virus. The indicator plants Chenopodium quinoa, C. amaranticolor, Nicotiana rustica and N. glutinosa were inoculated by sap inoculation. The virus produced systemic mosaic on N. glutinosa and N. rustica and necrotic local lesions on C. quinoa and on C. amaranticolor. The specific primer pair of CMV coat protein region was used in immunocapture reverse transcription-polymerase chain reaction (IC-RT-PCR), resulting amplification of a fragment with 700 bp length.The results demonstrated that CMV occurs in olive orchards in the region with symptoms varied from mild mosaic to leaf and fruits deformation. Cucurbit species growing in vicinity of olive trees in Tarom region may provide a unique chance for transmitting of CMV from its original host plants to olive trees. This is the first report of occurrence of CMV on olive or chards in Iran.

Alfalfa weevil, Hypera postica Gyllenahl and alfalfa root weevil, Sitona discoideus Gyllenahl, are native insects of alfalfa (Medicago sativa L.) in Iran that causing sever damages. Microctonus aethiopoides Loan is a solitary endoparasitoid of adult weevils of the genera Hypera and Sitona. Life cycle of this wasp and its potential and potential as biological control agent were studied both in laboratory and field conditions during 2009 – 2010 in Qazvin, Iran. In laboratory experiments (26 ± 1 °C, 70 ± 10 % R.H., 10:14 (L:D) photoperiod), developing times for egg-larvae and pupae were 14.73 ± 0.34 and 6.03 ± 0.11 days for males and 15.16 ± 0.19 and 7.12 ± 0.23 days for female respectively. Parasitism rate achieved to 41 and 1% on H.postica and S.discoideus respectively. The sex ratio (M: F) was different for the first (overwintered wasps) and second generation (0:1 and 1:1.2 respectively).The parasitic wasp had two generations per year and the first and the second generations of this wasp emerged at early April and October respectively. Both generations of the parasitoid wasp were well synchronized with adults of both weevils, resulting in parasitism rates of 15-33% and 9-15% on alfalfa weevil in the first and second generations but not more than 0.7% on root weevil. First instar larvae of the wasp overwinter within adult stage of their hosts.

Bean cultivars with various morphological features and genetic backgrounds show different responses to weeds that eventually may decrease the yield. This research was carried out during two years (2006-2007) to assess the ability of red bean cultivars to compete with some weeds. The experiment was performed as a split plot factorial based on randomized complete block design with three replications. Main plot included two levels (with and without) of weed. Sub plots had factorial combinations of different bean cultivars (Sayyad, Derakhsan and local cultivar of Zanjan province) and various plant densities (20, 30, 40 and 50 plants per square meter). included cultivars Sayyad, Derakhshan and local cultivar of Zanjan and planting densities were 20, 30, 40 and 50 plants per square meter. The space between planting rows was 30 cm. The number of weeds and thier dry weight per plot were determined three times in: third trifoliate leaf, 50% flowering and physiological maturity stages. The biomass of bean was measured in three stages as described above. Number of pods per plant, number of grains per pod, plant height, yield and one hundred grain weight for each plot were measured. Statistical analyses were performed using SAS, SPSS and EXCEL softwares and mean comparison of data was carried out using Duncans multiple range test. Results showed that Sayyad cultivar at densit of 40, Derakhshan cultivar at densit of 50 and local cultivar at densit of 30 and 40 plants per square meter had the highest biomass, yield and impact on reduction of weeds biomass.The results also showed that 40 bean plants per in the presence of weeds produced the highest bean biomass and yield and had the highest impact on reduction of weed biomass and density.