Journal Of Crop Protection
Volume:2 Issue: 1, Mar 2013

Ants consume or store the honeydew which is secreted by aphids or other homopteran insects. Major benefit of ant attendance for aphids is protection against natural enemies. A study was carried out during 2009-2010, to determine the mutualistic association between ants and aphids on different host plants in some parts of Khuzestan and Esfahan provinces. A total of 20 ant species belonging to 12 genera and 3 subfamilies were collected and identified. Among them, four species are new to Iranian ant fauna as follows: Monomorium libanicum Tohme; Monomorium qarahe Collingwood & Agosti; Monomorium mayri Forel and Lasius paralienus Seifert. The collected myrmecophilous aphids were 33 species belonging to 3 families and 5 subfamilies. Details and mechanisms of such associations between ants and aphids are unknown to us. More detailed investigations are needed in each case to adequately understand them.

The pink hibiscus mealybug Maconellicoccus hirsutus (Green) (Hemiptera: Pseudococcidae) is a serious economic pest in tropical and subtropical regions and causes damage to many agricultural, forestry and greenhouse crops. In order to identify the natural enemies of this pest, bi-weekly samplings were done in infested areas of Ahvaz, located at southwest Iran during 2011-2012. Samples were also taken from Chinese hibiscus shrubs, Hibiscus rosa-sinensis L. at two urban areas in Ahvaz to determine the pest population fluctuations. Other infested plants were also sampled for exploring natural enemies associated with M. hirsutus. The identified natural enemies in this study are as follows: Nephus arcuatus Kapur, Hyperaspis polita Weise, Hyperaspis vinciquerrae Capra, Exochomus nigripennis Erichson, Scymnus (Pullus) syriacus Marseul (Col., Coccinellidae) – Chrysoperla carnea (Stephens) (Neu., Chrysopidae) – Anagyrus sp. (Hym., Encyrtidae). Also one parasitoid of coccinellid larvae and three species of hyperparasitoids were identified as follows: Homalotylus quaylei Timberlake (parasitoid of coccinellid larvae), Prochiloneurus aegyptiacus (Mercet), Prochiloneurus bolivari Mercet (Hym., Encyrtidae) and Chartocerus kurdjumovi (Nikol’skaya) (Hym., Signiphoridae). The coccinellid H. vinciquerrae is new to the fauna of Iran. The natural enemies, i.e. N. arcuatus and Anagyrus sp. had the highest populations on the host plants throughout the year.

The essential oils of aerial parts of three medicinal plants Artemisia khorassanica Podl., Rosmarinus officinalis L. and Mentha longifolia L. were isolated by hydrodistillation and investigated for their toxicity and repellency against Tribolium confusum Jacquelin du Val. at 27 ± 1 ºC and 60 ± 5% RH in darkness. The mortality of the adults increased with concentration from 185 to 1111 μl/l air and with exposure time from 9 to 24 h. A concentration of 185 μl/l air and exposure time of 24 h was sufficient to obtain nearly 100% kill of the adults in all of the three essential oils tested. At the highest concentration (1111 μl/l air) R. officinalis oil caused 15% mortality for an exposure time of 6-h. whilst, the oil of A. khorassanica resulted in 1% mortality at the same exposure time. The oil of A. khorassanica at 1111 μl/l air caused 81% mortality for 12-h exposure time. No significant differences were observed between the lethal time (LT50) values at essential oil concentrations of 741 and 1111 μl/l air. For 24-h exposure time, the LC50 values of A. khorassanica, R. officinalis and M. longifolia essential oils were estimated to be 22.45, 22.14 and 39.96 μl/l air respectively. Based on LC50 values, adults of T. confusum showed similar susceptibility to the A. khorassanica and R. officinalis oils, but M. longifolia oil proved to be less toxic. In contrast to their low fumigant properties, the essential oil of M. longifolia had significantly higher repellency to T. confusum adults than did the other two.

This paper reviews the research on taxonomy of the Trombidioidea in Iran, with an updated checklist of 32 species (+5 undetermined species) belonging to five families and 22 genera. Among them, 27 species (+1 undetermined species) are reported based on larvae only, three undetermined species based on adults only, and six species based on both larval and post-larval stages. Also, 14 species (+3 undetermined species) and 10 genera belonging to the family Trombidiidae, one undetermined species belongs to the family Podothrombiidae, 13 species (+1 undetermined species) and seven genera belonging to the family Microtrombidiidae, three species, three genera belonging to the family Neothrombiidae and two species and one genus belonging to the family Achaemenothrombiidae. Major contributions to the Iranian fauna of the Trombidioidea were made by Alireza Saboori and his colleagues, and Zhi-Qiang Zhang. There have been some studies on the biology and the application of the Trombidioidea in biological control in Iran.

Medicinal plant powders have traditionally been used as grain protectants against stored-product insect pests. In this study, insecticidal activity of Carum copticum L. and Cuminum cyminum L. powders was assessed on adults of Sitophilus granarius L. and Tribolium confusum Jacquelin du Val. Experiments were carried out on wheat at 27 ± 1 ºCand 55 ± 5% r. h. The mortality increased with increasing concentration level and time exposed to each concentration. For S. granarius, 7 days and in case of T. confusum 14 days exposure time is sufficient to obtain considerable mortality. For example, 3500 mg/kg of C. copticum 7 days after treatment caused 80% on S. granarius; while for T. confusum 29% mortality was achieved and exceeded to 100% after 14 days. Therefore, it can be concluded that adults of S. granarius were more susceptible than T. confusum to plant powders. Also, according to the findings, C. cyminum powder has more insecticidal efficacy than C. copticum on both insects’ species. For S. granarius, 950 and 2700 mg/kg powders of C. copticum and C. cyminum was enough to cause ca. 50% mortality after 5 days, respectively. In case for T. confusum, 3200 and 4400 mg/kg of the plant powders caused same mortality after 7 days. Findings of the present study shows that the plant powders could be applied in grain protection of small-scale storage facilities.

Demographic parameters of the ladybeetle, Serangium montazerii Fursch feeding on citrus whitefly, Dialeurodes citri Ashmead were determined on two host plants, page tangerine and Thompson navel orange. This study was carried out under laboratory conditions (25 ± 1 °C and RH of 60 ± 5% and a photoperiod of 16: 8 h (L: D). Total pre-adult periods of the lady beetle were 20.84 ± 0.302, 19.27 ± 0.251days on Page tangerine and Thompson navel orange, respectively. The survivorship from egg to adult were very close to each other on two host plants. The oviposition periods were 29.64 ± 0.905 and 33.36 ± 0.599 days and the total number of eggs per female (fecundity) were 457.14 ± 11.099 and 528.57 ± 12.369 on Page tangerine and Thompson orange, respectively. Peaks of reproductive value occurred at ages of 31 and 33 days when reared on Thompson navel orange and page tangerine, respectively. The intrinsic rates of increase (r) on Thompson orange and on Page tangerine were 0.134 ± 0.063 and 0.126 ± 0.006d-1 with no significant differences. The mean generation time (T) on these host plants were 39.03 ± 0.5 and 40.57 ± 0.46 days, respectively. it can generally be concluded that S. montazerii feeding on D. citri showed a slightly better reproductive performance on Thompson navel orange than on Page tangerine.

Soil-dwelling mites and among them Gamasina (Acari, Mesostigmata) are widely distributed in soils, rich in species and have great ecological significance in the respective ecosystems. A survey was conducted to study Laelapidae (Mesostigmata) mites in Ahwaz (Khuzestan province), Iran during 2010-2012. Samples were taken from soil and litters and then mites extracted using Berlese funnel, cleared in lactic acid and mounted in Hoyer's medium. Among some species of this family, Gaeolaelaps jondishapouri n. sp., collected from soil is described and illustrated. G. jondishapouri n. sp. is characterized by dorsal shield with 39 pairs of setae (including Px2-3), r6 and R1-6 being off dorsal shield on soft lateral cuticle; posterior part of dorsal shield with abrupt contraction between S4 and S5 setae; st1 on weakly sclerotized pre-sternal area out of sternal shield, iv1-2 slit-like. A key to the adult females of the species of Gaeolaelaps with abrupt constriction in dorsal shield (Karg’s angusta species group) is provided.

A specimen of an ascomycetous fungus collected during a field trip was identified as Gymnoascus Baran. Soil samples collected from 0-20 cm depth were studied for isolation of fungi using a soil dilution plate method. Based on the morphological and molecular characters the specimens were identified as Gymnoascus reesii. Genomic DNA was extracted and a nuclear rDNA region, containing the internal transcribed spacers 1, 2 and 5.8S gene of rDNA (ITS) were amplified and PCR products were sequenced. Amplicon was purified, sequenced and submitted to the GenBank (Acc. No. JQ387570-71). The resulting sequence (600 bp) was submitted to a BLAST search to find most similar sequences in GenBank. The search results showed highest similarity of Iranian isolates to other isolates of G. reesii from GenBank. In the light of literature on ascomycetous fungi, Gymnoascus Baran is a new record for Iran mycoflora. The specimens are kept in fungal collection of the Department of Plant Protection, Razi University, Kermanshah, Iran.

The influence of leaf pubescence of three wheat cultivars (Pishtaz, Ghuds and Falat) on preference and biological parameters of Sipha maydis (Passerini) were investigated under greenhouse conditions (25 ± 2 °C, 70 ± 10% RH and 14: 10 h (L: D) photoperiod). The results showed that Pishtaz had a maximum density of trichomes compared to the other cultivars. In the preference test with whole plant, the number of aphids on Pishtaz was significantly greater than that on other cultivars at 48 hrs after infestation. Similarly, in the preference test with leaves, the numbers of attracted aphids per leaf was highest on Pishtaz. In the life table study, there was no significant difference of intrinsic rate of natural increase (rm) among the three studied cultivars but it was highest on Pishtaz (0.187 /day). Aphids’ net reproductive rate, doubling time, mean generation time and finite rate of increases did not show significant difference between the tested cultivars. According to our results, leaf surface pubescence of wheat is not an effective resistance mechanism against S. maydis.

The potato tuber moth (PTM), Phthorimaea operculella Zeller (Lepidoptera: Gelechiidae), is an important pest of potato and other solanaceous plants. It is cosmopolite and oligophage that exist in most countries where potatoes are grown. Because of chemical treatment adverse effects, there is a necessity to find safe alternatives to synthetic insecticides. So, medicinal plants are promising since they are safe, inexpensive and effective. In this direction, potato tubers were dipped in 1 ml of 5% methanolic extracts of fumitory, licorice, lavender and oregano. The percentage of first larval penetration to tubers and oviposition-preference of mentioned medicinal plants was investigated on PTM. Subsequently, fumigant toxicity of essential oils of basil, european pennyroyal, lavender, mint and savory were investigated on P. operculella. Treated potato tubers by methanolic extract of lavender elicited the lowest percentage (19.3) of first larval penetration. Studying of oviposition-preference demonstrated that the most number of eggs were laid on control and fumitory with 28 and 10 eggs after three days, respectively. Probit analysis of essential oils showed that the most effective oil was savory which exhibited LC50 value on adults of PTM equivalent to 0.048 µL/L air.

The genus Conophorus Meigen, 1803 (Diptera: Bombyliidae: Conophorini) was studied in the north and northwestern parts of Iran. Three species of the genus Conophorus were identified; two of them are recorded for the first time from Iran, namely: C. pseudaduncus Paramonov, 1929 and C. rjabovi Paramonov, 1929, in addition to C. glaucescens (Loew, 1863), which was previously recorded in Iran. Morphological characters, geographical distributions, and an identification key for the three collected species are provided.