Applied Entomology and Phytopathology
Year:2009 | Volume:- | Issue:(87-PESTICIDES SPECIAL ISSUE)|Papers Count:11

Termites utilize only cellulosic materials. This feeding behaviour from point of agriculture has made termites an important group of pests. A group of termites, so-called harvester termites, damage pastures. Some species of termites damage farm plants, fruit and ornamental trees. Nevertheless, the control of termites in agriculture has been investigated worldwide, particularly, in tropical and subtropical regions. Currently, baiting system is one of the best methods of termite control. In this method, a negligible amount of slow-acting toxicant is impregnated in cellulosic materials. Foragers collect poisoned materials to the colony and through trophalaxis phenomenon it is transfered to other individuals. In this circumstance, epidemic will be occurred in the colony. In current research, baiting system was investigated in a 2 hectares date palm orchard of Saravan region. Experiments were conducted with factorial design including 2 factors (each factor with 3 levels) and 3 replicates leading to dividing the date palm orchard to the 30 experimental units. Acid boric (0.5 and 1 percent) and Hexaflumuron (200 ppm) were evaluated as treatments. Data were analyzed with paired sampled t-test. Results indicated that the means of termite population before and year after baiting were significantly different. Also, the means of termite population before and 18 months after baiting were significantly different. Analysis of factorial experiments indicated that there was a difference within level of factor A (number of bait trap per experimental unit). Within levels of factor B (termiticides), no difference was observed. There was no interaction between factors A and B.

A set of field and greenhouse experiments were conducted in 2004-2005 to study antagonistic effects of 2,4-D plus MCPA with clodinafop propargyl in wheat. The field experiments were conducted in Maybod and Oroumieh, where tank mixture of 2,4-D plus MCPA at 0, 975 and 1300 g ai ha-1, with clodinafop propargyl at 0, 64, 80, 96 and 112 g ai ha-1 in factorial arrangement and four replications per treatment. Hoary cress (Cardaria draba (L.) Desv.), littleseed canarygrass (Phalaris minor Retz.), haresear mustard (Conringia orientalis (L.) Dumort.) and downy brome (Bromus tectorum L.) were the dominant weed species in the field experiments. Greenhouse experiments further evaluated the efficacy of these tank mixtures on prostrate knotweed (Polygonum aviculare L.), littleseed canarygrass and poison ryegrass (Lolium temulentum L.). In the field, herbicides were applied at wheat tillering while in the greenhouse the herbicides were applied at the beginning of tillering stage and at four-leaf stage of grass and broadleaf weeds, respectively. The most satisfactory tank mixture was 2,4-D plus MCPA at 975 and 1300 g ai ha-1 with clodinafop propargyl at 96 g ai ha-1. Yield increased when tank mix of clodinafop propargyl with 2,4-D plus MCPA was applied on wheat. To prevent clodinafop propargyl efficacy reduction due to tank mixing with 2,4-D plus MCPA, the application dose (64 g ai ha-1) should be increased to 96 g ai ha-1.

For nearly 50 years, insecticides have been used for sunn pest control. The foliar spraying is the most widely used application method in Iran. More than 75 percent of total sprayed areas belong to ground application and the rest is covered by aerial application. Hydraulic lance sprayers (HLS) are the most common ground sprayer used in sunn pest control. Financial restraints such as the cost of labor, water and environmental pollution have necessitated new techniques. A HLS was compared with a Controlled Droplet Application (CDA) or micronair to find the most effective way to spray fenitrothion for control sunn pest nymphs in wheat field. Three micronair treatments (fenitrothion EC 50% at 0.5, 0.75 and 1 L/ha), one HLS treatment (fenitrothion EC 50% at 1.3 L/ha) and control were tested in a randomized complete block design with 4 replications. This experiment was carried out at three nymphal stages of sunn pest (2nd, 4th and 5th). Only micronair treatment at 0.5 L/ha was significantly less efficient than the other treatments (85±1.9%) in control of sunn pest nymphs. But the rest of micronair treatments controlled sunn pest nymphs in the same rate as HLS treatment (93.43-95.32%). In all of the micronair treatments, insecticide deposit on high canopy was more than HLS treatment. The waste of spray and mechanical damage to wheat fields by CDA were much lower than by HLS. The CDA is light and easy to use and requires 10-50 liter of spray per hectare wheras HLS requires 200-400 L/ha. The CDA is proper sprayer for fields where the conventional sprayers even aerial sprayer, could not be used. It is concluded that light weight, accurate delivery and controlled droplet application in CDA create a more efficient technique to apply pesticides being unavailable before.

Sex pheromone is known as an important tool for monitoring and control of Tortrix viridana L. (Lep.: Tortricidae). In this regard, trap shape and pheromone dispensers could play important role in successful programs. In this study the shape of pheromone traps including delta, cylindrical, rectangular and wing traps examined as a probable effective factor in capturing of T. viridana in west Azarbaijan, Kurdistan and Fars provinces. Experiments were conducted in randomized block designs with four treatments and four replicates (each replicate contained 2-3 traps). Traps were installed on middle height canopy of oak trees, following first emergence of males. Captured males were counted every 10-15 days. Same experiment was designed for studying the effect of pheromone dispensers on tortrix male capturing with 6 type of dispensers in Azarbaijan forest. All of conditions were same as previous experiment.Maximum capture was observed in Azarbaijan province by delta traps (mean =110.66±5.2). Whereas, in Kurdistan maximum captured moth was observed in cylindrical traps (59.1±9.95) placed in same group with delta and rectangular traps. In Fars province with low density of pest population cylindrical traps had maximum rate of moth capture (15±2.5) however, there was no significant differences between traps in these regions. Results indicated that in high and medium population density of the pest, trap shape had effective role in male capture. Results obtained in experiments showed that pheromone dispensers have an important role in capturing rate of T. viridana. Maximum captures observed in dispensers made of soft silicon (mean 114±24.2 males per trap) and soft rubber with one ostiole (mean=322.7±13.36) compared to the other traps.

Date palm fruit stalk borer, Oryctes elegans prell. (Col.: Scarabaeidae) is one of the most important pests of palm trees in Iran and Asia. 4-methylOctanoic acid has been identified as the essential component of the male aggregation pheromone of O.elegans. Synthesis of 4-methylOctanoic acid has been performed in 4 steps at chemical laboratory of Iranian research institute of plant protection. In the 1st step addition reaction of leuvinic acid and bromo butane afforded 4-Hyydroxyoctanoic acid. In the 2nd step chloride is replaced with hydroxyl group by the addition of ethanol-chloride and thionyl chloride to give 4-chloro 4-methylOctanoic acid. In the next step by heating the resulting compound it produced unsaturated alkene bond of 4-methyl 3-Octenoic acid. To saturate alkene bond, hydrogenation with platinum oxide as catalyst has been done. Final compound resulted after vacuum distillation and column chromatography, 69 gram pure racemic mixture of 4-methyloctanoic acid in total efficiency of 48%. This method of synthesis is easy and reproducible in any chemical laboratory.Field test in date palm groves of Saravan region established and concluded that there is no significance difference between synthesized pheromone and imported one. Hence this pheromone can be prepared in Iran because of low cost of preparation and enhance availability and use in mass trapping programs to reduce population.

Considering the necessity of omission of monocrotophos from tobacco budworm, Helicoverpa armigera, control program, tests were carried out to assess the effect of indoxacarb, as an alternative in years 2005-2006. The experiments were conducted at randomized complete block design, using indoxacarb (Avant SC 15%) at rates ranging 200, 250, and 300 ml/ha, and conventional insecticides thiodicarb (Larvin DF 80%) at rate of 1 kg/ha and monocrotophos (Nuvacron SL 40%) at rate of 2 l/ha. Percent mortality was calculated using Henderson-Tilton formula at 1 and 3 days after spraying. A repeatedmeasures analysis, general linear model (GLM), indicated a significant difference among treatments for percent mortality of budworm. Both indoxacarb and thiodicarb caused a high mortality of the larvae, whereas monocrotophos revealed the lowest effect. In general, Avant SC 15% at the rates between 200 and 250 ml/ha is recommended for controlling tobacco budworm.

Amount of acaricidal used on apple mite pests (Tetranychus urticae Koch and Panonychus ulmi Koch) were recorded more than any other crops damaged by spider mite in Iran. Effects of three doses (0.4, 0.5, 0.6 per thousand) of new acaricides spirodiclofen SC 240, evaluated in comparison with two other registered acaricides i.e. fenazoquen 20% SC and clofentazine 50% SC on active stages, egg and two injury level of P. ulmi (ERM) and active stages of T. urticae (TSPM) on red and golden varieties of apple orchards in Tehran, Khorasan, West Azarbaijan, Ardebil and Esfahan provinces during 2003. The BCRD method was used to assign 4 replications of five treatments along with an untreated check plots. Mean mortality % recorded one day before and 3, 7, 14 and 25 days after treatments and mortality% calculated by Henderson-Tilton method. Analysis of variance on mean collected data carried out by SAS method and mean mortality% also grouped with DMRT method. Application of treatments initiated when mean observed of 3 and 5 active stages P. ulmi and T. urticae, respectively. Treatments effects on ERM active stages showed that, except Clofentazine and all treatments in Ardebil, reached to the mortality above 80%. Maximum control % recorded for doses of spirodiclofen 0.5 and 0.6 doses in Tehran and W. Azarbaijan provinces, respectively. Treatment effects at sampling interval found varied and except in Esfehan observed at increasing level up to 7 days after with 92.29% of spider mite inTehran. Decreasing mite mortality of those treatments also recorded 14 days onward with maximum 87.7% control at 25 days interval in Khorasan. Ovicidal effects of clofentazine were found weak against egg stage of ERM in comparison to other treatments. Acaricidal effects on low number of ERM in late spring observed more effective than when mite population ranging between 5-10 mites/leaf during hot and dry condition in middle of summer months. Control measures on active stages of TSSM in apple orchard of Esfehan with mean of 10 to 12 mites/leaf was found more effective than in Tehran with mean of mite was ranging between 2.08-3.43 mites/ leaf. Maximum mortality of TSSM among treatments recorded 96.15% and 86.14% for fenazoquen, and spirodiclofen dose 0.6/liter water respectively in Tehran province. Side effects of Spirodiclofen on apple natural enemies observed with less hazardous to adult of Stethrous spp only fourteen days after treatments.

In Golestan province, three field trials were conducted to evaluate the efficacy of preemergence herbicides diuron, prometryn and alachlor, respectively at 2, 2 and 1.92 kg ai ha-1, in control of weeds and their selectivity on cotton (Sahel cultivar). In the first experiment (first year), the herbicides were used alone or tank mixed with each other to compare them with weedy check and weed-free check. In the two other experiments (second year), the efficacy of broadcast and band application of diuron and prometryn was evaluated. In the second year experiments, inter-row cultivation was carried out one month after planting in all treatments except in weedy check. In band application, the application rate of the herbicides was reduced to 50%. In all experiments, the herbicides caused no visual injuries on cotton cv. Sahel and all treatments, compared with weedy check, significantly controlled the weed species. In control of Amaranthus retroflexus, Chenopodium album, Solanum nigrum and Abutilon theophrasti, diuron and prometryn were better than alachlor. Whereas, the effect of alachlor on Echinochloa crus-galli, was better than that of the other herbicides. Diuron was significantly more effective in control of S. nigrum than prometryn. Despite inter-row cultivation, band application of diuron or prometryn was less effective than broadcast application in control of S. nigrum, A. retroflexus and A. theophrasti. Broadcast application of diuron or prometryn, accompanied with inter-row cultivation, in addition to sufficient control of weeds, resulted in higher cotton lint yield than the other treatment. Cotton lint yield loss in weedy checks in the experiments was evaluated 54 to 95 percent.

Chemical control measurements are the only control methods used against codling moth (Cydia pomonella L.) in Iran. In this respect, it is of primary importance to determine the effects of the routinely applied insecticides on the other organisms in the orchards. Some experiments have been carried out on 8 following chemicals: Stamipride, lufenoron, Indoxicarp (two dosage), phosalon, Azinphosmethyl, Phenproparthin, Hexaflomoron and Calypso in Taleghan region of Tehran province.In this region, Codling moth has two generations annually. First spray against codling moth coincides with the flight and oviposition of Ermine moth (Hponomeuta malinellos) in apple orchards. To determine the overall effect of the insecticides on these two pests, we have considered the number of ooplacqus of Ermine moth laid on the twigs along with the estimation of the number of infested apples by codling moth. In addition, we tried to find out the relation, if any, of various insecticides with the occurrence of rust on the fruits. The results obtained, showed significant differences between the insecticides regarding the above mentioned goals.There was also significant differences in the density of ooplacqus on the twigs and also the number of first instar larva under each ooplacq at the (a=1%). As regards the occurrence of russeting, Biobaca, Stamipride and Azinphosmethyl, had produced significantly more russeting than the other chemical compounds.