Feeding performance and life table parameters of Khapra Beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae) on various barley cultivars.

The Khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae), is a common pest of cereal grains and other stored products. In this study, the effects of ten barley cultivars (Abidar, Bahman, Line20, Line22, Line30, Lisuei, Lokht11, Makuyi, Sahand, and Sahraa) were evaluated on life table parameters and nutritional indices of T. granarium under the following laboratory conditions: 33 ± 1°C, 60 ± 5% RH, and a photoperiod of 14: 10 (L: D) h. Life history parameters of T. granarium could be appropriate indices in resistance and susceptibility evaluation of barley cultivars. The maximum survival rate of immature stages was observed on Makuyi and Lisuei cultivars and the minimum rate was on Abidar and Line22 cultivars. The shortest development time was on Makuyi cultivar and the longest on Line22 cultivar. Pupal weight was ranged from 2.56 mg on Lokht11 to 4.86 mg on Makuyi. Fecundity and egg-hatching rates were highest on Lisuei cultivar and the adults were long-lived on Makuyi cultivar. The highest r m values were observed on Makuyi and Lisuei cultivars but lower value of it resulted from rearing of T. granarium on Line22 cultivar (0.0350 female per female day-1). The results showed that T. granarium larvae fed on Makuyi cultivar had higher values of relative consumption rate and relative growth rate. The results indicated that Makuyi and Lisuei cultivars were relatively susceptible barley cultivars and Line22 was the most inappropriate cultivar for feeding of T. granarium, which could prove useful in the development of Integrated Pest Management programs for this pest.

Population Growth Parameters of Rose Aphid, Macrosiphum rosae (Hemiptera: Aphididae) on Different Rose Cultivars.

The rose aphid, Macrosiphum rosae (L.), is one of the most important pests on rose plants (Rosa spp.) with a worldwide distribution. As resistance indices, the development, survivorship, and reproduction of this aphid were evaluated on 10 rose cultivars, including Bella Vita, Cool Water, Dolce Vita, Maroussia, Orange Juice, Pinkpromise, Roulette, Tea, Valentine, and Persian Yellow in laboratory at 25 ± 1°C, 65 ± 5% relative humidity, and photoperiod of 16:8 (L/D) h. Rose aphid successfully survived on all 10 rose cultivars, although mortality rate was higher on Tea and Bella Vita. The number of offspring per female differed significantly among the tested rose cultivars, and ranged from 9.2 on Tea to 38.7 nymphs on Orange Juice. Population growth parameters were significantly affected by rose cultivars. The longest mean generation time (T) was observed on Bella Vita (14.8 days) and Tea (14.7 days) and the shortest on Orange Juice (10.0 days). The net reproductive rate (R 0 ) ranged from 6.9 on Tea to 33.2 nymphs on Orange Juice cultivar. Correspondingly, the highest value of intrinsic rate of increase (r m ) was observed on Orange Juice (0.348 day-1) and lower values on Tea (0.131 day-1) followed by Bella Vita (0.154 day-1). Cluster analysis of all the measured parameters of rose aphid on different rose cultivars revealed that Tea and Bella Vita were relatively resistant to M. rosae. These findings could be useful in developing an integrated pest management (IPM) program for this aphid in urbanized areas and commercial rose potting.

Susceptibility of Five Sugar Beet Cultivars to the Black Bean Aphid, Aphis fabae Scopoli (Hemiptera: Aphididae).

The black bean aphid, Aphis fabae Scopoli (Hemiptera: Aphididae), is one of the important pests of sugar beet. The relative impact of resistance, including antibiosis and antixenosis of five sugar beet cultivars (Doroti, Perimer, Pershia, Rozier and 006) on A. fabae was studied under laboratory conditions using clip cages. The antibiosis test was based on life table parameters. Significant differences on developmental time, mean number of nymphs/aphid/day, fecundity, and adult longevity of A. fabae were found across tested sugar beet cultivars. In addition, there were significant differences among the sugar beet cultivars for population growth parameters such as the intrinsic rate of natural increase (r m ), net reproductive rate (R 0), finite rate of increase (λ), doubling time (DT), and mean generation time (T) of A. fabae. The highest and lowest (r m ) values were observed on Pershia (0.449 nymphs/female/day) and Perimer (0.358 nymphs/female/day), respectively. No significant differences were found for the preference of the black bean aphid, and antixenosis had no effect on resistance against this aphid. As a result, our findings showed that the Pershia cultivar was a relatively susceptible host plant. Two cultivars (Perimer and Rozier) were relatively resistant to A. fabae, which could prove useful in the development of IPM programs for this aphid in sugar beet fields.

Digestive enzymatic activity and nutritional responses of Helicoverpa armigera (Lepidoptera: Noctuidae) larvae fed various tomato cultivars.

Digestive enzymatic activity and nutritional responses of sixth-instar larvae of the tomato fruit borer, Helicoverpa armigera (Hübner), were studied on eight tomato cultivars commonly cultivated in Iran. Among various tomato cultivars, the larvae fed on 'Cal JN3' (4.860 +/- 0.092 U/mg) significantly showed the highest level of proteolytic activity. However, proteolytic activity of the larvae reared on 'Sun 6108 f1' (2.182 +/- 0.161 U/mg) was significantly lower than those reared on Cal JN3, 'Korral,' 'Rio grande UG,' 'Super crystal,' and 'CH falat'. Also, the larvae fed on Korral (0.170 +/- 0.007 mU/mg) significantly had higher amylolytic activity than the other tomato cultivars. The pupal weight of H. armigera was significantly lower on Rio grande UG (0.208 +/- 0.014 g), Sun 6108 f1 (0.216 +/- 0.008 g),and Super strain B (0.229 +/- 0.014 g) than Cal JN3 and CH falat. Because the larvae and pupae reared on Rio grande UG were lighter than those fed on the others, this cultivar can be suggested as the least suitable host for feeding of H. armigera. However, because the mean weight gain of the larvae, food consumption, and larval weight during feeding period were significantly highest on CH falat, it can be selected as suitable cultivar for feeding of the pest.

Comparative life history and fecundity of Phthorimaea operculella (Lepidoptera: Gelechiidae) on leaves and tubers of different potato cultivars.

The potato tuberworm, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), is a noxious pest of the potato crop (Solanum tuberosum L.) in both field and storage in tropical and subtropical regions. Survival, development and reproduction of the potato tuberworm was compared on leaves and tubers of 10 common cultivated potato cultivars including Agria, Agata, Almera, Arinda, Baneba, Fiana, Marfona, Ramus, Satina, and Volvox at 25 +/- 1 degree C, 65 +/- 5% RH and a photoperiod of 14:10 (L:D) h. The results indicated that there were significant differences in the larval, pupal, and total developmental periods on the various potato cultivars. The total developmental periods varied from 26.6 (on Baneba) to 29.5 d (on Marfona),and ranged from 27.9 (on Marfona) to 30.5 d (on Agria) in the experiments on potato leaves and tubers, respectively. Immature survival rates were lowest on Agria (44.1%) and Marfona (40.6%) on potato leaves and tubers, respectively. The highest total fecundity was observed on Arinda (78.3 eggs) and Ramus (154.8 egg) on potato leaves and tubers, respectively. Significantly fewer eggs were laid on Marfona cultivar's leaves (44.6 eggs) and tubers (72.9 eggs) than any of the other tested potato cultivars. The female reproduction potential on potato leaves was significantly lower than on potato tubers. Cluster analysis of the biological parameters of P. operculella on different potato cultivars demonstrated that Marfona is partially resistant to potato tuberworm. The findings on the susceptibility or resistance of potato cultivars could be a fundamental component of integrated pest management programs for potato tuberworm.

Effect of different host plants on nutritional indices of the pod borer, Helicoverpa armigera.

Nutritional indices of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) on different host plants including chickpea (cultivars Arman, Hashem, Azad, and Binivich), common bean (cultivar Khomein), white kidney bean (cultivar Dehghan), red kidney bean (cultivar Goli), cowpea (cultivar Mashhad), tomato (cultivar Meshkin) and potato (cultivars Agria and Satina) were studied under laboratory conditions (25 ± 1 °C, 65 ± 5% RH, 16:8 L:D). Third instar larvae reared on potato Agria showed the highest efficiency of conversion of digested food (ECD) and efficiency of conversion of ingested food (ECI) (50.800 ± 0.104% and 13.630 ± 0.016%, respectively). Approximate digestibility (AD) values of the fourth instar larvae were highest (92.651 ± 0.004%) and lowest (57.140 - 0.049%) on chickpea Azad and potato Agria, respectively. The fifth instar larvae fed on tomato Meshkin and white kidney bean Dehghan had the highest consumption index (CI) (3.717 ± 0.091) and relative consumption rate (RCR) (1.620 ± 0.074), respectively. Whole larval instars showed the highest ECI and ECD values on potatoes Satina (14.640 ± 0.014%) and Agria (21.380 ± 0.015%), respectively, and the lowest of both values on tomato Meshkin (ECI: 5.748 ± 0.002% and ECD: 7.341 ± 0.002%). The results of nutritional indices and the cluster analysis indicated that tomato Meshkin was an unsuitable host for feeding of H. armigera.

Digestive proteolytic and amylolytic activities and feeding responses of Helicoverpa armigera (Lepidoptera: Noctuidae) on different host plants.

Digestive proteolytic and amylolytic activities and feeding responses of fifth instar larvae of Helicoverpa armigera (Hübner) on different host plants including chickpea (cultivars Arman, Hashem, Azad, and Binivich), common bean (cultivar Khomein), white kidney bean (cultivar Dehghan), red kidney bean (cultivar Goli), cowpea (cultivar Mashhad), tomato (cultivar Meshkin), and potato (cultivars Agria and Satina) were studied under laboratory conditions (25 +/- 1 degrees C, 65 +/- 5% RH and a photoperiod of 16:8 [L:D] h). Our results showed that the highest protease activity in optimal pH was on cultivar Dehghan (8.717 U/mg) and lowest one was on Meshkin (3.338 U/mg). In addition, the highest amylase activity in optimal pH was on cultivar Dehghan (0.340 mU/mg) and lowest was on Meshkin (0.088 mU/mg). The larval weight of fifth instar H. armigera showed significant difference, being heaviest on Binivich (125.290 +/- 5.050 mg) and lightest on Meshkin (22.773 +/- 0.575 mg). Furthermore, the highest and lowest values of food consumed were on Goli (362.800 +/- 27.500 mg) and Satina (51.280 +/- 4.500 mg), respectively. In addition, the lowest values of prepupal and pupal weight were on Meshkin (32.413 +/- 0.980 and 41.820 +/- 1.270 mg, respectively). The results indicated that tomato (Meshkin) was unsuitable host for feeding fifth instar larvae of H. armigera.

Resistance of wheat lines to Rhopalosiphum padi (Hemiptera: Aphididae) under laboratory conditions.

Bird cherry-oat aphid, Rhopalosiphum padi (L.), a polyphagous species with a nearly worldwide distribution, is an important pest of wheat as well as the main vector of barley yellow dwarf virus. We evaluated the resistance categories of eight wheat lines including antibiosis, antixenosis, and tolerance against R. padi under laboratory conditions. The wheat lines tested were ERWYT 88-8, ERWYT 87-6, and ERWYT 87-4 (resistant); ERWYT 87-1, ERWYT 87-20, and ERWYT 88-11 (susceptible); ERWYT 88-12 and ERWYT 88-13 (intermediate). In the antibiosis experiment, R. padi produced fewest progeny on ERWYT 88-8, ERWYT 87-6, and ERWYT 87-4 in reproduction period. In the antixenosis test, R. padi performed best on ERWYT 87-1, ERWYT 87-20, and ERWYT 88-11. Fewer apterous aphids selected ERWYT 88-8, ERWYT 87-4, and ERWYT 87-6 lines indicating antixenosis of these lines to R. padi. In tolerance experiments, however growth parameters differed between treated and untreated seedlings of wheat lines with 10 aphids per day infestation during 21-d period, but not among eight wheat lines. The plant resistance index values were greatest for ERWYT 88-8 (9.71), followed by ERWYT 87-4 (7.04) and ERWYT 87-6 (4.76). ERWYT 88-8, ERWYT 87-6, and ERWYT 87-4 may be important sources of R. padi resistance for small grain breeding and integrated pest management programs.

Life table parameters of Phthorimaea operculella (Lepidoptera: Gelechiidae), feeding on tubers of six potato cultivars.

The potato tuberworm, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), is an important and ubiquitous pest of potato, Solanum tuberosum L. (Solanaceae), in both field and stores in the subtropical and tropical zones. The evaluation of potato tubers for susceptibility to potato tuberworm, by measuring its life table parameters, is a valuable component of integrated pest management (IPM). Potato tuberworm life table parameters were investigated in laboratory at 24 +/- 1 degrees C, 65 +/- 5% RH, and a photoperiod of 8:16 (L:D) h on six commonly grown potato cultivar tubers: 'Agria', 'Burren', 'Savalan', 'Marfona', 'Sante', and 'Picaso'. No food was provided to feeding adult moths during experiments. The survival rate on Savalan and Burren potatoes was higher than on other cultivars. The highest reproductive rate was observed on Burren potatoes (50.739 +/- 2.45), although there was one statistical group for net reproduction rate (R(o)). The mean generation time (T(o)) was the longest on the Agria potatoes. The significant difference was observed between intrinsic rates of increase (r(m)) on the potato cultivars. The mean generation time has reciprocal relation with r(m); subsequently, the lowest intrinsic rate of increase was observed on Agria potatoes. The highest and lowest r(m) value was observed on Burren and Agria potatoes, respectively. The descending order of intrinsic rates of increase was on Burren, Savalan, Sante, Marfona, Picaso, and Agria potaotes. The lowest r(m) value indicates that Agria is a relatively insusceptible compared with the other cultivars tested and that this cultivar can be used effectively in sustainable IPM.

Life table and temperature-dependent development of Diadegma anurum (Hymenoptera: Ichneumonidae) on its host Plutella xylostella (Lepidoptera: Plutellidae).

Life table and temperature-dependent development of Diadegma anurum (Thomson) (Hymenoptera: Ichneumonidae) was studied on diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae) reared on cabbage, Brassica oleracea L. variety capitata, and cauliflower, Brassica oleracea L. variety botrytis. The developmental periods of immature stages were recorded at five constant temperatures (15, 20, 25, 30, and 35 degrees C). The population of D. anurum and its host failed to survive at 35 degrees C. Mean total development time of D. anurum was not significantly different on two host plants except at 25 degrees C. The developmental zero (low temperature threshold) was estimated to be 7.0 and 6.9 degrees C, and the thermal constant was 282.3 and 277.7 DD on cabbage and cauliflower, respectively, using the linear model. Data were fitted to four nonlinear temperature-dependent models. Evaluation of the models was carried out based on the following criteria: fit to data, number and biological values of the fitted coefficients, and accuracy on the estimation of the thresholds. Consequently, the Briere-1 model was accepted and recommended for the description of temperature-dependent development of D. anurum. The life table parameters of D. anurum were also studied at 25 degrees C constant temperature. Its intrinsic rate of increase (rm) and mean generation time (T) were estimated to be 0.169 and 16.083 d on cabbage, respectively. The life table parameters of D. anurum can be used to develop the models of population dynamics and prediction.