Inhibitory effects of cold atmospheric plasma on population growth of the carob moth, Ectomyelois ceratoniae (Lepidoptera: Pyralidae) in laboratory.

Potential sterilizing effects of the atmospheric cold plasma on the carob moth, Ectomyelois ceratoniae Zeller (Lepidoptera: Pyralidae) was studied under laboratory conditions by means of life history experimentation. The results showed that the population growth parameters of the carob moth decreased in all periods of 15 to 60 sec of plasma treatments applied on 1 -day-old eggs. Overall, 19.5% and 23.8% of reproduced eggs were fertile when the experimental males and females mated with normal moths in indirect treatments of 15 and 30 sec, respectively. The highest intrinsic rate of population increase, r, was in control (0.11 day-1) and the highest decrease in this parameter was in the 30 sec direct treatment (- 0.073 day-1). The results showed that cold plasma had an acceptable potential to sterilize the pest if plasma was applied at egg stage. This potential will be explored from the perspective of insect sterility technique and the genetical / physiological mechanisms involved should be studied in future.

Effect of Different Fruit Developmental Stages and Biochemical Metabolites of Pomegranate (Ponicaceae) on Life History Parameters of Ectomyelois ceratoniae (Lepidoptera: Pyralidae).

Plant-herbivore interactions can be influenced by plant developmental stages. Effects of four different developmental stages of pomegranate fruit (Hazelnut size, Walnut size, Juicy, and Ripe) were investigated on life table parameters, nutritional yield, and energy contents (protein, glycogen, and lipid) of Ectomyelois ceratoniae (Zeller) under controlled conditions in two pomegranate cultivars, namely Shahvare-Danesefid and Esfahani-Daneghermez as susceptible and resistant cultivars, respectively. Biochemical characteristics of the four developmental stages were determined, and a correlation was made with life-history and nutritional responses of E. ceratoniae. Significant differences were observed in developmental time and adult fecundity of E. ceratoniae across various tested stages in both pomegranate cultivars. The highest value of intrinsic rate of increase (rm) was found in Juicy and lowest in Hazelnut-size stage of Shahvare-Danesefid. The highest rm value was on Walnut-size and Juicy stages, and the lower rate was obtained from the feeding of E. ceratoniae on Ripe and Hazelnut-size stages in Esfahani-Daneghermez. A higher relative growth rate (RGR) was observed in Juicy (in Shahvare-Danesefid) and Walnut-size stages (in Esfahani-Daneghermez) when compared with other developmental stages tested. Life-history parameters of E. ceratoniae were correlated with biochemical qualities of pomegranate stages. Results indicated Juicy (Shahvare-Danesefid) and Walnut-size stages (Esfahani-Daneghermez) were relatively susceptible pomegranate stages, and Hazelnut-size and Ripe stages were unsuitable for feeding of E. ceratoniae in Shahvare-Danesefid and Esfahani-Daneghermez, respectively. Findings of this research could aid in the development of integrated management programs of E. ceratoniae in pomegranate orchards.

Relationship Between Performance of Carob Moth, Ectomyelois ceratoniae Zeller (Lepidoptera: Pyralidae) and Phytochemical Metabolites in Various Pomegranate Cultivars.

The carob moth, Ectomyelois ceratoniae Zeller (Lepidoptera: Pyralidae), is the main pest of pomegranate, Punica granatum L., in Iran and many parts of the world. In this study, the effects of 11 commercial cultivars of pomegranate (Aban-Mahi, Esfahani-Daneghermez, Gabri, Gorche-Tafti, Malase-Danesyah, Malase-Yazdi, Shahvare-Daneghermez, Shahvare-Danesefid, Tabolarze-Mehrmahi, Tafti, and Toghe-Gardan) were evaluated on life history variables, nutritional performance, and energy reserves of E. ceratoniae under the following laboratory conditions: 30 ± 1°C, 60 ± 5% RH, and a photoperiod of 14:10 (L:D) hours. In addition, biochemical characteristics of the tested cultivars were assessed in order to understand any possible correlation between important demographic parameters and nutritional properties with biochemical features of pomegranate juice. Our research showed that various pomegranate cultivars have significant effects on life history, demographical parameters, nutritional indices, and energy reserves of E. ceratoniae. The shortest development time was observed on Shahvare-Danesefid cultivar and the longest was on Esfahani-Daneghermez and Malase-Danesyah cultivars. The highest intrinsic rate of increase (r m ) was observed on Shahvare-Danesefid and the lowest was on Esfahani-Daneghermez. Six major anthocyanin compounds were detected in juice of various pomegranate cultivars. Significant positive or negative correlations were observed between life history variables and nutritional characteristics with biochemical traits of pomegranate cultivars. The results indicated that Shahvare-Danesefid was a relatively susceptible pomegranate cultivar and Esfahani-Daneghermez was the least appropriate (most resistant) cultivar for feeding of E. ceratoniae, which could be useful in the development of integrated pest management strategies for this pest.

Thermal Requirements and Development Response to Constant Temperatures by Nesidiocoris tenuis (Hemiptera: Miridae), and Implications for Biological Control.

Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae), a common zoophytophagus bug, is a biological control agent for several groups of noxious agricultural pests, including whiteflies, aphids, and leafminers. To improve mass-rearing of this species and to optimize its application in integrated pest management, nymphal survival and developmental times of this predator were examined at seven constant temperatures ranging from 14 through 34°C. Eggs developed to adulthood at all temperatures tested. Egg-adult developmental time decreased sharply with increasing temperature, except at 34°C (17.21 d), for which developmental time was significantly longer than that obtained at 31°C (15.59 d). The lowest (11.36%) and highest (28.26%) percentage of mortality was found at 28 and 14°C, respectively. To describe the development rate of immature stages of N. tenuis as a function of temperature, two linear and 26 nonlinear models were fitted. The lower temperature threshold (T0) and thermal constant (K) of total immature stages were estimated by the ordinary (10.94°C and 318.37 DD) and Ikemoto (10.28°C and 339.57 DD) linear models. Based on the Akaike information criterion (AIC), Lactin-1, Analytis-1/Allahyari and Janisch/Kontodimas were the best models to describe the temperature-dependent development rate of egg, nymph and whole immature stages of the predator, respectively. Our findings provide information on N. tenuis biology that will improve application of this predator as a biological control agent.

Finish line plant-insect interactions mediated by insect feeding mode and plant interference: a case study of Brassica interactions with diamondback moth and turnip aphid.

There are gaps in our understanding of plant responses under different insect phytophagy modes and their subsequent effects on the insect herbivores' performance at late season. Here we compared different types of insect feeding by an aphid, Lipaphis erysimi, and a lepidopteran, Plutella xylostella, and how this affected defensive metabolites in leaves of 2 Brassica species when plants gain maturity. Thiocyanate concentrations after P. xylostella and L. erysimi feeding activities were the same. Total phenolics was higher after the phloem feeder feeding than the folivore activity. The plants compensatory responses (i.e., tolerance) to L. erysimi feeding was significantly higher than the responses to P. xylostella. This study showed that L. erysimi had higher carbon than P. xylostella whereas nitrogen in P. xylostella was 1.42 times that in L. erysimi. Population size of the phloem feeder was not affected by plant species or insect coexistence. However, there was no correlation between plant defensive metabolites and both insects' population size and biomass. This suggests that plant root biomass and tolerance index after different insect herbivory modes are not necessarily unidirectional. Importantly, the interaction between the folivore and the phloem feeder insects is asymmetric and the phloem feeder might be a trickier problem for plants than the folivore. Moreover, as both plants' common and special defenses decreased under interspecific interference, we suggest that specialist insect herbivores can be more challenged in ecosystems in which plants are not involved in interspecific interference.

How Different Genetically Manipulated Brassica Genotypes Affect Life Table Parameters of Plutella xylostella (Lepidoptera: Plutellidae).

The fitness of Plutella xylostella L. on different genetically manipulated Brassica plants, including canola's progenitor (Brassica rapa L.), two cultivated canola cultivars (Opera and RGS003), one hybrid (Hyula401), one gamma-ray mutant-RGS003, and one transgenic (PF) genotype was compared using two-sex and female-based life table parameters. All experiments were conducted in a growth chamber at 25±1°C, 65±5% relative humidity, and a photoperiod of 16:8 (L:D) h. There were significant differences in duration of different life stages of P. xylostella on different plant genotypes. The shortest (13.92 d) and longest (24.61 d) total developmental time were on Opera and PF, respectively. The intrinsic rate of increase of P. xylostella ranged between 0.236 (Opera) and 0.071 day(-1) (PF). The highest (60.79 offspring) and lowest (7.88 offspring) net reproductive rates were observed on Opera and PF, respectively. Comparison of intrinsic rate of increase, net reproductive rates, finite rate of increase, mean generation time, fecundity, and survivorship of P. xylostella on the plant genotypes suggested that this pest performed well on cultivars (RGS003 and Opera) and performed poorly on the other manipulated genotypes especially on mutant-RGS003 and PF. Glucosinolate levels were significantly higher in damaged plants than undamaged ones and the lowest and highest concentrations of glucosinolates were found in transgenic genotype and canola's progenitor, respectively. Interestingly, our results showed that performance and fitness of this pest was better on canola's progenitor and cultivated plants, which had high levels of glucosinolate.

Bottom-up effect of different host plants on Plutella xylostella (Lepidoptera: Plutellidae): a life-table study on canola.

The effects of 10 commercial canola, Brassica napus L., cultivars widely grown in Iran--'SLM(046),' 'Opera,' 'Okapi,' 'RGS(003),' 'Modena,' 'Sarigol,' 'Zarfam,' 'Licord,' 'Hayula(420),' and 'Talaye'--on the demographic parameters of diamondback moth, Plutella xylostella L. (Lepidoptera-Plutellidae), were determined. The experiments were conducted in a growth chamber at 25 +/- 1 degrees C, 65 +/- 2% RH, and a photoperiod of 16:8 (L:D) h. The comparison of intrinsic rate of natural increase (r(m)), net reproductive rate (R0), and the survival rate of adult stage of P. xylostella on 10 canola cultivars suggested that this pest performed best on SLM(046). The r(m) value of P. xylostella ranged between 0.241 on RGS(003) and 0.304 on SLM(046). The R0, finite rate of increase (lambda), mean generation time (T), and doubling time (DT) values of P. xylostella on SLM(046) were 52, 1.35, 13.4, and 2.35 and on RGS(003) were 31, 1.27, 14.4, and 2.94, respectively. The Weibull model adequately described the shape of the survivorship curve of adult P. xylostella from life-table data. A significant fit was obtained with the Weibull model for P. xylostella in all experimental canola cultivars. As a result, SLM(046), Opera, and Hayula(420) were the most suitable hosts and had least negative impact on life-history statistics of the pest.