جستجوی مقالات مرتبط با کلیدواژه "predators" در نشریات گروه "گیاهپزشکی"

Cultivation of diverse crops is a strategy key in sustainable agriculture. Increasing plant diversity in intercropping systems can be suitable for biological control of pests. In order to investigate the effect of mixed cultivation of sugar beet and red clover on the population of Aphis fabae Scopoli, natural enemies including Coccinella septempunctata Linnaeus, Hippodamia variegata Goeze, Orius niger Wolf, O. minutus Linnaeus, and Chrysoperla carnea Stephens, and some agricultural traits of sugar beet, an experiment was conducted in the form of completely randomized block design in four replications. Experimental treatments included monoculture of sugar beet (control) and seven types of strip cultivation systems including: 1) two rows of sugar beet  and four rows of red clover, 2) two rows of sugar beet and three rows of red clover, 3) one row of sugar beet and two rows of red clover, 4) two rows of sugar beet and two rows of red clover 5) three rows of sugar beet and two rows of red clover, 6) two rows of sugar beet and one row of red clover, 7) four rows of sugar beet and two rows of red clover. The results of this research showed that the different treatments of sugar beet and red clover intercropping on the aphid population, natural enemies, and agricultural traits including root yield, leaf yield, and shoot yield are significant at 1% probability level. The results of this research showed that the treatment of two rows of sugar beet and four rows of red clover can be useful in integrated pest management and biological control of A. fabae in sugar beet fields and improve agricultural traits.

In a faunistic study on the edaphic Mesostigmata in Mahan City in center of Kerman Province, soil samples were collected from different habitats, their mites extracted using Berlese-Tullgren funnels, cleared in Nesbitt’s fluid and then identified after mounting in Hoyer's medium on microscope slides. Totally, 34 species belonging to 26 genera and 15 families of Mesostigmata were collected, including female and male specimens of Pergamasus (Thenargamasus) quisquiliarus (G. & R. Canestrini) that was considered as the first record of the subgenus and species from Iran. List of the collected mites and also morphological attributes of the new recorded mite were presented. Additionally, the pergamasine mites of Iran and their classification were revised and a key to the Iranian genera and species was provided. Additionally, Hypoaspis sclerotarsus Costa was transferred to the genus Hypoaspisella Bernhard and diagnostic morphological features of the species were presented.

Poplar trees are among the fast-growing trees and they have a special place in plantation and wood products. Poplar clear wing moth Paranthrene tabaniformis (Rott.) is a major pest of these trees. Each year, in the poplar nurseries, the seedlings of these trees are attacked by this pest, resulting in severe damage to the production of wood and its dependent industries. In this study, normal control of population of these butterflies was evaluated by Dendrocopos syriacus (Hemprich & Ehrenberg) woodpecker. For this purpose, 2217 seedlings from 10 different poplar clones were selected in one of the nurseries at Astaneh-Ashrafieh Poplar Research Station in Guilan province. At the end of the growing season, it became clear all 670 seedlings were infected with galls. In the next step, the activity of woodpeckers and the effect of diameter and height growth characteristics of gall-contaminated seedlings on woodpecker hunting were evaluated by multiple regression analysis and Pearson correlation. The results of this study showed that Syrian Woodpeckers are capable of operating more than 36% on some infected seedlings, and in this regard, the amount of their activity intensifies with the growth of the diameter and height of the seedlings infected with the gall.

Background and Objectives:

 The melon aphid, Aphis gossypii Glover, is one of the most important pests of tomato in Iran. This aphid causes severe damage on tomato crop in northern Iran. 

Materials and Methods:

 Present study was conducted in an experimental field, 0.3 h, in Behshahr region in Mazandaran province based on a randomized completely block design. In this study, the effectiveness of intercropping tomato (T) with clover (C) in the three combinations: (1) one row of tomato with two rows of clover (1T:2C), (2) two rows of tomato with two rows of clover (2T:2C), and (3) three rows of tomato with two rows of clover (3T:2C) along with sole tomato were assessed on the densities of melon aphid, Aphis gossypii Glover, diversity of its natural enemies and yield of both crops in 2016 and 2017.

 Results:

 The density of nymphs and adults of A. gossypii were significantly higher in sole tomato compared with intercrops. Among intercrops, the lowest density of nymphs and adults of A. gossypii were observed in 1T:2C intercrop. In present study, 13 predator species were collected and identified on aphid-infested plants of tomato in the experimental field. Among the predators, Coccinella septempunctata L., Chrysoperla carnea (Stephens) and Episyrphus balteatus DeGeer had more abundance in the two studied years.  The Shannon diversity index (H´) and the Pielou’s evenness index (J´) for composition of predator species were significantly higher in intercrops compared with sole tomato crop. Moreover, more nymphs and adults of A. gossypii were parasitized in all intercrops compared with sole tomato crop in 2016 and 2017. The highest value of land equivalent ratio was found in 1T: 2C (LER = 1.28 in 2016 and 1.30 in 2017) among intercrops in the two cropping seasons.   

Discussion:

 All the three intercropping patterns of tomato with clover including 1T:2C, 2T:2C and 3T:2C, especially 1T:2C could be recommended in management programs of the melon aphid in tomato fields.

In this research, the influence of eggplant monoculture (E), soybean monoculture (S), and three intercropping systems including two rows of eggplant with four rows of soybean (2E: 4S), two rows of eggplant with two rows of soybean (2E: 2S) and four rows of eggplant with two rows of soybean (4E: 2S) were studied on population densities of Tetranychus urticae Koch, diversity and abundance of its predators, and yield of both crops in an experimental field based on a randomized block design with four blocks during two cropping seasons (2016 - 2017). In both years, the densities of T. urticae eggs and mobile forms on eggplant and soybean were significantly lower in the three intercrops compared to monoculture systems (P < 0.05). Moreover, the densities of T. urticae eggs and mobile forms were significantly higher on the soybean than the eggplant in each monoculture and intercrop system. The Shannon’s diversity indexes (H') for T. urticae predators on eggplants were significantly higher in the three intercrops compared to the monoculture. Furthermore, the values of this index were greater in soybean monoculture and 2E: 4Sintercrop than 2E: 2Sand 4E: 2S systems (P < 0.05). Values of the land equivalent ratio (LER) were higher in 2E: 4S relative to other intercrop systems in both years. Therefore, it could be concluded that 2E: 4S intercrop is the most suitable cropping system for using in integrated management of T. urticae in eggplant and soybean fields.

  The European corn borer, Ostrinia nubilalis (Hübner), is an important pest of corn in Iran. Intercropping systems has been proposed as one approach that can be used for reducing pest density and improving biodiversity of natural enemies and crop yield. Therefore, the present research assessed the densities of immature stages of O. nubilalis, biodiversity of its predators, and parasitism rates of immature stages in experimental plots where corn was grown either as monoculture or strip-intercropped with sunflower. We also evaluated the effect of the intercropping systems with natural infestation of O. nubilalis on corn yield. In this research, the influence of five strip-intercropping systems of corn (C) and sunflower (S)including 2C: 2S, 4C: 2S, 8C: 2S, 4C: 4S, and 2C: 4S along with corn monoculture was studied on density of imaginal stages of O. nubilalis, its natural enemies biodiversity, the percentage of parasitized eggs and larvae, and the grain yield of corn and the percentage of grain yield loss in an experimental field in Ardabil region in 2016 and 2017. These experimets were conducted in a randomized block design with four replicates. The densities of imaginal stages (eggs, larvae and pupae) of O. nubilalis in intercrops were significantly lower than corn monoculture. Among the natural enemies of this moth, Orius niger (Wolff), Lydella thompsoni Herting, Bracon hebetor Say and Trichogramma brassicae Bezdenko had the high relative abundance in the tested cropping systems. The Shannon diversity index (H') in intercrops was significantly greater than in corn monoculture. The calculated values of Morisita–Horn index for the predator’s species composition between intercrops were CMH ≥ 0.946 in 2016 and CMH ≥ 0.934 in 2017. In both years, the percentage of parasitized eggs and larvae of O. nubilalis in intercrops was significantly higher than in corn monoculture. The highest grain yield of corn and the lowest percentage of grain yield loss of corn were found in 8C: 2S intercrop. Based on the resource concentration hypothesis, the lower density of O. nubilalis and the lower percentage of infested plants in the intercropping systems of corn and sunflower could be demonstrated by overlapping of the secreted volatile compounds of two crops that caused disruption in the host finding. Moreover, based on the enemies hypothesis, the higher attraction and conservation of predators and parasitoids in intercrops caused lower density of O. nubilalis than in corn monoculture. In this study, the competition for nutriants between corn and sunflower was also reduced with increasing of the corn rows between the sunflower rows; the percentage of grain yield loss of corn was reduced in 8C: 2S copmpared to other intercrops. Therefore, it could be concluded that 8C: 2S intercrop is the most suitable intercropping system for use in integrated management of O. nubilalis in corn fields

In this research, the influence of intercropping systems (including three, six and nine rows of green bean, Phaseolous vulgaris L. with alternate three rows of clover, Trifolium resupinatum L.) and monoculture of green bean on biodiversity of the onion thrips, Thrips tabaci Lindeman and the proportion of predators/prey density were studied in an experimental field in the Ardabil during 2015 and 2016 years. In this study, 21 species of onion thrips predator were collected and identified that among them, the predator species Aeolothrips intermedius Bagnalland and Orius niger (Wolff) had the highest relative abundance in each of cropping systems. The Shannon diversity index (H) in each of the three intercrops was significantly greater than in green bean monoculture. The values of Morisita–Horn index (CMH) between green bean monoculture and each of the three intercrops (CMH ≤ 0.85) were lower in comparison with the values of this index among the three intercrops (CMH ≥ 0.94). In two years, the proportion of predators/prey and the density of the onion thrips predators especially two dominant species A. intermedius and O. niger in each of the three intercrops were significantly higher than in green bean monoculture. Therefore, it can be concluded that strip-intercropping of green bean with clover caused higher biodiversity of the onion thrips predators and reduced the density of T. tabaci. Application of the mentioned strip-intercropping systems in the green bean fields as one of the important components in the integrated management of the onion thrips is recommended.

The Colorado potato beetle, Leptinotarsa decemlineata (Say) (Col.: Chrysomelidae) is the most important phytophagous pest of potato in Iran. In this research, diversity and abundance of terrestrial predators, and density of Colorado potato beetle eggs, larvae and adults were studied in potato rows located at 5, 10, 15, and 20 m from the alfalfa field (in the potato field adjacent to the alfalfa field) along with the control (the sole potato field) in Ardabil region during 2014 and 2015. In this study, eight terrestrial predator species in the control potato field and fourteen terrestrial predator species in the potato field adjacent to the alfalfa field were collected using pitfall trap and identified, amongst which spiders and carabid beetles had more relative abundance. The Shannon diversity index (H’) for terrestrial predators in the potato rows located at 5, 10, 15, and 20 m from the alfalfa field (in the potato field adjacent to the alfalfa field) was significantly higher than in the control potato field. During two years, the abundance of spiders and Carabid beetles decreased with increasing distance of the potato rows from the alfalfa field. Moreover, the density of Colorado potato beetle eggs, larvae and adults increased with increasing distance of the potato rows from the alfalfa field. Therefore, use of the strip cropping of potato and alfalfa (with 10 m of the potato strips width) could be recommended to the farmers in the integrated management of Colorado potato beetle.

The European corn worm, Ostrinia nubilalis (Hübner) is an important pest of corn in Iran. In this research, the influence of corn monoculture and also, three strip-intercropping systems including three, six and nin rows of corn with three rows of clover were evaluated on the natural enemies diversity of O. nubilalis, the proportion of predators/prey density and finally, the percentage of parasitized eggs and larvae in experimental fields in Ardabil region in 2014 and 2015. In this study, eight predator species, five larval parasitoid species and one egg parasitoid species were collected and identified which amongst them, Orius niger (Wolff), Lydella thompsoni Herting, Bracon hebetor Say and Trichogramma brassicae Bezdenko had the high relative abundance in the tested cropping systems. The Shannon diversity index (H) in each of the three intercrops was significantly greater than in corn monoculture. The values of Morisita–Horn index (CMH) between corn monoculture and each of the three intercrops (CMH ≤ 0.893) were lower in comparision with the values of this index among the three intercrops (CMH ≥ 0.977). In two years, the proportion of predators/prey, and the percentage of parasitized eggs and larvae of O. nubilalis in each of the three intercrops were significantly higher than in corn monoculture. Implementation of these cultivation systems in the corn fields is an important step in the management of O. nubilalis.

The Comstock mealybug, Pseudococcus comstocki (Kuwana), is a polyphagous pest distributed in the world, as well as Iran. Several species of mulberries, Morus spp, are infested with P. comstocki in Tabriz, East-Azarbaijan province. In the present study, natural enemies of P. comstocki are studied during 2012-2013. As a result, nine insect species of predators, parasitoids and hyperparasitoids associated with the pest were collected and identified as follows: Aphelinidae: Marietta pictaAndré; Encyrtidae: Anagyrus novickyi Hoffer, Coccidoxenoidesperminutus Girault, Echthroplexiella flava Mercet; Pteromalidae: Pachyneuron muscarum (L.); Signiphoridae: Chartocerus kurdjumovi Nikolskaya; Cecidomyiidae: Diadiplosis sp.; Chamaemyiidae: Leucopis sp.; Coccinellidae: Chilocorus bipustulatus L. Within this assemblage, Echthroplexiella flava is new record for Iranian insect fauna. Based on available literature, C. kurdjumovi, M. picta and P. muscarum are hyperparasitoids of the mealybug. The population fluctuation and relative abundance of this association in Tabriz were studied in 2013 and the Anagyrus novickyi was successfully reared for the first time on P. comstocki.

The role of aculeate wasps in natural control and natural balance of arthropod pests is discussed. They are predator or parasitoid on a wide range of insects and other arthropods. Some species may potentially be applied as biological control agents. Some activities for supporting or enhancing their population are discussed. The Iranian aculeate wasp fauna is also reviewed and the most common species in the families Vespidae, Scoliidae, Sphecidae, Crabronidae, Mutillidae, Formicidae, Chrysididae, Tiphiidae, Bethylidae, Pompilidae and their hosts are listed.

The wheat thrips، Haplothrips tritici Kurd.، is an important pest of wheat crop، Triticum aestivum L.، in Ardabil region، northwestern Iran. Strip cropping of wheat and alfalfa، Medicago sativa L.، is a suitable strategy for improving the effectiveness of biocontrol agents of the wheat thrips. In this research، population density of the wheat thrips، and species richness and abundance of its predators were studied in the strip cropping of wheat and alfalfa (three-year old) and the monoculture of wheat during field surveys from 2010 to 2011. Sampling from each of two wheat cropping systems was conducted from the stem elongation until ripening stages. Number of the wheat thrips and predators per plant were recorded in each sample date. The population density of the wheat thrips in the strip cropping of wheat-alfalfa was significantly lower than that of monoculture of wheat. Five species of predators were recorded in the monoculture of wheat and 15 species of predators were recorded in the strip cropping of wheat-alfalfa. The Shannon diversity index for predators in the strip cropping of wheat-alfalfa was significantly higher than that for monoculture of wheat. The Morisita-Horn index between two wheat cropping systems was calculated 0. 842. The species richness and abundance of predators in the strip cropping of wheat-alfalfa were greater than the monoculture of wheat. Therefore، it can be concluded that the strip cropping of wheat-alfalfa increases the species diversity of the predators and reduces the population density of H. tritici. Quantifying the species richness and abundance of predators in the wheat fields is an important step in the management of the wheat thrips.