Showing 9 results for Greenhouse
H. Ghahari, B. Hatami,
Volume 4, Issue 2 (7-2000)
Abstract
The difficulties of control of greenhouse whitefly on crops and greenhouse plants make extensive studies and investigations necessary in different areas of Iran. Morphological and biological studies were carried out on a prevailing species of greenhouse whitefly, Trialeurodes vaporariorum Westwood, in Isfahan.
In this study, six species of whiteflies T. vaporariorum on Althaea sp. and Lantana camara, Bemisia tabaci Gennadius, B. argentifolii Bellows & Perring and B. hancoki Corbett, on Lantana camara, Aleyrodes proletella L. on Brassica sp. and Aleyrodes rosae on Rosa sp. were collected. These species were described using different identification keys. Morphological characteristics and different growth stages of greenhouse whitefly including egg, 1st to 4th nymphal instars and adult were defined and figures drawn. Biological studies were conducted in 24±1°C, 65±5% RH and 16:8 (L:D) on eggplant, solanum melongena. The developmental time for egg, 1st, 2nd, 3rd and 4th nymphal instars was 7.33±0.48, 3.37±0.52, 3.25±0.45, 2.51±0.26 and 7.66±0.83 days, respectively. The total period from egg to adult lasted 24.12±0.51 days. The number of eggs laid in 24 hours varied between 1 to 10 with an average of 5.93±1.67. Life-span of the male ranged between 19 to 23 with an average of 20.88±1.54 and that of the female varied between 20 to 28 with an average of 26.44±1.17 days. Four nymphal instars were identified and three substages for the 4th nymphal instars were determined. There was a positive correlation between nymphal instars and average body length and width. Since only male offsprings were produced through parthenogenesis, the strain of greenhouse whitefly in Isfahan was found to be European.
Z. Ahmadzadeh, B. Hatami,
Volume 7, Issue 3 (10-2003)
Abstract
Greenhouse whitefly, Trialeurodes vaporariorum West. is one of the most important pests of the field crops and ornamental plants in greenhouses. Pest control is based on using chemical insecticides and biological control agents. In this study, the efficiency of the green lacewing, Chrysoperla carnea ( Steph.) with release ratios of 1:1, 1:5, 1:10, 1:15, and 1:20 (predator:prey) using eggs in chrysobag and the effect of three insecticides including Confidor (35% Sc), Permethrin (25% Ec) and Dimilin (25% Wp) at concentrations of 0.3 ml/l, 0.3 ml/l and 0.15 g/l in water, respectively, were investigated. In one experiment, the eggs of the green lacewing were released on tomato plants that were infested with 150 different nymphal instars of the pest. Control treatment included chrysobag whithout any egg. After 11 days, nymphal mortality was calculated. In insecticidal experiments, in control treatment, only water was sprayed. Both experiments were conducted in a randomized complete block design with four replications in a greenhouse with 25±5 °C, 50-60% RH and 14:10 LD period light conditions. The means of data were compared using Duncan Multiple Range Test. The results showed that the maximum nymphal mortality of 52.42% was due to the release ratio of 1:1 (predator:prey) however, this was not sufficient and did not control the pest population. The results of the chemical control also revealed that one application of Confidor caused the highest mortality about 88% that was more effective in reducing pest population compared with the release of predator eggs. Neither method had absolute control. In general, results indicated that to be more effective the two methods need to be applied more than once, and they must be combined into one or with other control methods.
J. Keramat, Kh. Talebi, L. Mosaffa,
Volume 9, Issue 1 (4-2005)
Abstract
Vegetable crops are exposed to repeated spraying against the pests and diseases during the growing sessions. Crops such as greenhouse cucumber are usually harvested a short time after spraying, bearing a high level of pesticides with them. This fact justifies a research on this problem. This research was carried out to determine the effects of metalaxyl (a fungicide commonly used in greenhouse) residue in cucumbers grown under traditional and modern greenhouse conditions. Cucumber plants were sprayed with two different doses: 1/1 000 and 2/1000 metalaxyl in modern and traditional greenhouses. Samples were collected 1, 2, 4, 7, 10, 14, 21 and 28 days after spraying with metalaxyl. The fungicide residue was extracted, cleaned up by TLC and the final solution was analyzed by HPLC. Data were analyzed statistically by t-test (paired observations) and Duncans multiple range test.
The results revealed that the amount of metalaxyl residues increased in the first four days following spraying. This amount of the residue was 10 times higher than MRL (0.5 mg/kg), while a lower level of MRL (0.5 mg/kg) was detected 21 days after the application. Results also showed that a lower dose of application left a higher residual level than the higher one. On the other hand, no significant differences (p<0.05) were found between the amounts of residues in peeled and unpeeled cucumbers. Thus, fruit peeling does not reduce the fungicide residue in cucumber. Also, there were no significant differences (p<0.05) between the results obtained from modern and traditional greenhouses. Therefore, cucumber must either be harvested before or at least 14 days after spraying with metalaxyl.
Z. Ahmadzadeh, B. Hatami,
Volume 9, Issue 4 (1-2006)
Abstract
Greenhouse whitefly, Trialeurodes vaporariorum West., is one of the most important pests of field crops and ornamental plants in greenhouses which usually controlled by chemical insecticide and/or by biologic control factors. In this study the effect of singular and integrated use of Confidor and predator, Chrysoperla carnea (Steph.) against different nymphal instars of the pest on tomato plant was investigated. This experiment was carried out in 7 treatments, each in 3 replicates. Treatments included predator alone, the use of insecticide alone, and 4 integrated treatments of both the predator and insecticide. The predator was released at 5, 10, 15 and 20 day intervals after insecticide application. The control (water), insecticide spray and release of the predator were repeated each 10 days. In integrated treatments, insecticide was applied only once at the beginning of the experiment. The results showed that there was a significant difference between treatments. Pest control was not achieved with one or two attempts of release of predator or spray of insecticide. Pest elimination was only observed after third spray in insecticide treatment and 3 releases of predator beginning 20 days after spray in integrated treatment. These two treatments were shown to be of equal effectiveness in pest control. Also pest population was controlled after 5 releases which began 5 days after insecticide application. The use of the alone predator was statistically found to be less effective than treatment with the insecticide alone. Generally, integrated treatment is a promising alternative approach to pest control in longterm. It has clear advantages over chemical control in terms of pest resistance, environmental and general pest control issues. .
M. Shabanian, H. Masomi, A. Hoseinipour, J. Heidarnejad, Z. Azami,
Volume 11, Issue 1 (4-2007)
Abstract
Cucumber cultivars, grown in greenhouse in the Jiroft region, were surveyed for the relative incidence of Zucchini yellow mosaic virus (ZYMV), Watermelon mosaic virus-2 (WMV-2), Cucumber mosaic virus (CMV) and Tomato spotted wilt virus (TSWV) from 2001 to 2004. Samples from 1294 plants representing different cultivars were analysed by Enzyme-linked immunosorbent assay (ELISA) and Dot immunobinding assay (DIBA). The data showed that green-house cucumbers are infected by CMV, ZYMV, TSWV and WMV-2. However, ZYMV was the most prevalent virus. Mixed infection including double and triple infection was identified in some samples. Transmission of aphid-borne viruses (CMV, ZYMV and WMV-2) by Aphis gossypii, A. fabae, A. craccivora and Myzus persicae revealed that ZYMV is most efficiently vectored by these aphids and, A. craccivora transmitted these viruses with more than 60% efficiency. In addition, WMV-2 was not transmitted by A. gossypii. In RT-PCR, ZYMV infection was confirmed by amplifying a PCR product of the predicated size 458 bp, using total RNA extracted from infected plants. All ZYMV infected samples reacted with monoclonal antibodies (705-1, 705-2 and 705-4) in TAS-ELISA test. These results showed that ZYMV isolate collected from Jiroft belongs to group A, cluster 1 or 2. In electron microscopy study, normal length of ZYMV flexuous particles in partial purified preparation was calculated as 790 nm. The molecular weight of coat protein of ZYMV was estimated at 36 KDa., using SDS-PAGE and western blotting. This is the first report of these viruses in greenhouse grown cucumber in the Jiroft region.
H. Mehrabi Basharabadi,
Volume 12, Issue 44 (7-2008)
Abstract
Kerman province is the largest producer of greenhouse cucumber and tomato in Iran. This paper calculates the interest rate of return (IRR) and return period of investment (RPI) in vegetable, cut flowers and strawberry in greenhouse and compares them with vegetable grown outdoors. To do the study, a random sample of 309 farmers was selected in the province of Kerman in 2005. Results showed that IRR for vegetable, cut flowers and strawberry in greenhouse was about 20, 14 and 23 respectively, and it was 45/8 percentage per year for vegetable outdoors. RPI for vegetable, cut flowers and strawberry in greenhouse was about 8, 29, and 7 years, respectively. Vegetables Production under greenhouse produces more employment opportunities, has better yields, higher price and efficient use of factors, but it has lower IRR, higher production cost, higher pesticide residue and is more capital intensive in comparison with outdoor production. Improvement of greenhouse credits, enlargement of metal greenhouses, research on yield and development of greenhouses at region 5 are the important policy-making implications of this paper.
Mahdipuor, Landi,
Volume 14, Issue 52 (7-2010)
Abstract
An increase in the emission of greenhouse gases such as carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) from the soil surface to the atmosphere has been of worldwide concern over the last several decades. Carbon dioxide is recognized as a significant contributor to global warming and climatic change, accounting for 60% of total greenhouse effect. The aim of this research was to determinate the emission of greenhouse gases from different land under agricultural uses. Four types of agricultural land farm, including wheat field, canola field, citrus garden and fallow land were selected to investigate the fate of CO2 in these fields. Gas chromatography technique and close chamber method were used to analyze soil gas samples. Total carbon losses from soil in form of greenhouse gases was 4.47, 3.72, 3.38 and 1.89 Mg C ha-1 yr-1 for wheat field, canola field, citrus garden and fallow land, respectively. Total additional carbon to soil from biomass for wheat field and canola field was 4.1 and 4.6 Mg C ha-1 yr-1, respectively. ECB (ecosystem carbon budget) = ∑ C input - ∑ C output. For wheat field and canola field ECB was -0.37 and +0.88, respectively. This indicated that in wheat field carbon was lost and in canola field carbon was sequestrated. Under citrus garden due to changes in soil organic carbon form previous year has showed that carbon was sequestrated.
A. Sanaei Ostovar , A.h. Khoshgoftarmanesh , M.h. Mirzapour ,
Volume 14, Issue 54 (1-2011)
Abstract
This study was conducted to investigate nutritional status and some quality aspects of greenhouse cucumber in Qom province. After selecting 20 greenhouses, concentrations of macro- and micronutrients as well as lead (Pb) and cadmium (Cd) in soil and plant were measured. In addition, some fruit quality attributes were determined. Phosphorus (P) and potassium (K) concentrations in soils were much higher than their critical levels. The mean concentrations of soil DTPA-extractable iron (Fe), copper (Cu), and manganese (Mn) were 12.0, 1.98, and 14.5, respectively. The mean concentration of calcium (Ca) in cucumber leaf was high while in fruit was lower compared to its sufficiency level. Most fruit samples were deficient in K, Fe, Zn, Cu, and Mn. The mean nitrate (336 mg kg-1) and Pb (0.34 mg kg-1) concentrations in cucumber fruits were higher than their acceptable levels. Ascorbic acid concentration of fruits showed positive correlation with Fe concentration. Also, fruit Mg concentration had a positive correlation with the total dissolved solids and negative correlation with fruit moisture content. The results indicated that improper nutrition management in Qom cucumber greenhouses has caused micronutrients deficiencies and high nitrate and Pb concentration, which are important to consumers' health.
S. Jamali, H. Ansari, M. Zeynodin,
Volume 25, Issue 1 (5-2021)
Abstract
The goal of this study was to investigate the effects of treated urban wastewater and different harvesting times on the yield and yield components of Sorghum (cv. Speed feed) in the greenhouse condition. The research was done based on a completely randomized design including 3 replications as pot planting in Ferdowsi university of Mashhad in 2016. In this study, the effects of four mixtures consisting of the moderations use of the treated urban wastewater and freshwater (0, 25, 75 and 100 percent mixture of treated urban wastewater and freshwater) and three harvesting times level (pre-flowering, after 50 percent of the plant to flowering, and grain filling stage) on the yield and yield components of Sorghum were evaluated. The results inducted that the effect of different moderations of irrigation regimes on all of them parameter was highly significant (P<0.01), but plant height was non-significant; it was also revealed that the effect of harvesting times on all of the parameters was highly significant (P<0.01), but leaf width was non-significant. The results also exhibited that the interaction effects of irrigated regimes and harvesting times on the leaf number, panicle length and width, leaf, panicle, and stem was highly significant (P<0.01), but plant height, stem diameter, branches number, and leaf length and width were significant at the 5 percent level (P<0.05). Also, the use of 25, 75, and 100 percent mixture of wastewater resulted in the forage yield of 37.5, -29.3, and 12.9 percent (pre-flowering); -31, -15.3, and -47.4 percent (after 50 percent of the plant to flowering), and -11.8, -35.7 and -28.4 percent (grain filling stage), respectively. The highest forage weights (46.2 g per plant) showed, in the study, irrigated by a mixture of 75 treated wastewater and 25 freshwater, and harvesting the plant after 50 percent in flowering stage; on the other hand, the best treatment in this study irrigation by the mixture of 75 treated wastewater and 25 freshwater and harvesting the plant after 50 percent in the flowering stage, Thus, using the treatment in farm experiment required the field research.
