Potential of Essential Oils from Anise, Dill and Fennel Seeds for the Gypsy Moth Control

The gypsy moth (Lymantria dispar L. (Lepidoptera: Erebidae)) is a serious pest of hardwood forests. In the search for an environmentally safe means of its control, we assessed the impact of different concentrations of essential oils (EOs) from the seeds of three Apiaceae plants (anise Pimpinella anisum, dill Anethum graveolens, and fennel Foeniculum vulgare) on behavior, mortality, molting and nutritional physiology of gypsy moth larvae (GML). EOs efficacy was compared with commercial insecticide NeemAzal®-T/S (neem). The main compounds in the Eos were trans-anethole in anise; carvone, limonene, and α-phellandrene in dill; and trans-anethole and fenchone in fennel seed. At 1% EOs concentration, anise and fennel were better antifeedants and all three EOs were more toxic than neem. Neem was superior in delaying 2nd to 3rd larval molting. In the 4th instar, 0.5%, anise and fennel EOs decreased relative consumption rate more than neem, whereas all three EOs were more effective in reducing growth rate, approximate digestibility and efficiency of conversion of food into body mass leading to higher metabolic costs to GML. Decrease in consumption and metabolic parameters compared to control GML confirmed that adverse effects of the EOs stem from both pre- and post-ingestive mechanisms. The results indicate the potential of three EOs to be used for gypsy moth control.

Eugenol and Thymol Derivatives as Antifeedant Agents against Red Palm Weevil, Rhynchophorus ferrugineus (Coleoptera: Dryophthoridae) Larvae

Coconut palms in Malaysia are infested by a destructive invasive pest, RPW since 2007, and the pest’s population is difficult to control. At present, RPW control management mainly relies on the use of monocrotophos, which is administered by the trunk injection method. However, this pesticide can negatively impact human health and the ecosystem. Plant EO that can be used as a bio-pesticide is highly recommended as an alternative to monocrotophos because of its target-specific and eco-friendly properties. The antifeedant activity of eight eugenol and thymol derivatives from clove and thyme EOs were tested against the fourth instar larvae of RPW through oral bioassay for 14 days. Relative growth rate (RGR), relative consumption rate (RCR), the efficiency of conversion of ingested food (ECI), and the feeding deterrent index (FDI) were compared and analyzed. All of the derivatives showed antifeedant activity, particularly the eugenol derivative, 4-allyl-2-methoxy-1-(4-trifluoromethyl-benzyloxy)-benzene (FDI = 54.14%) and the thymol derivative, 2-isopropyl-4-methyl-2-((4-nitrobenzyl) oxy) benzene (FDI = 53.88%). Both of them showed promising results on their ability to be the most effective antifeedant agents in each derivative group. There was no significant difference in the effectiveness of the eugenol-based and thymol-based derivatives, but the ether derivative group (FDI = 45.63%) had a significantly stronger effect than the ester derivative group (FDI = 39.71%). This study revealed that the compound in ether form is more effective than the compound in ester form as an antifeedant agent against RPW larvae, regardless of the plant EO that the compound is derived from.

Nutritional Responses of the Black Cutworm, Agrotis ipsilon (Hufn.), Larvae under Toxicity Effects of Five Wild Botanical Extracts from Sinai, Egypt

Aims: To identify the chemical components of five wild Botanical oils (BOs) and their larvicidal influences on the anti-nutritional indices of the 4th instar larvae of Agrotis ipsilon. Study Design: A comparative study with the randomized design, using five plant Extracts replicated five times. Place and Duration of Study: Mentha longifolia, Artemisia judaica, Majorana hortensis, Origanum syriacum, and Achillea santolina were collected from the Sinai desert, Egypt. Study procedures were done at the Laboratory of Botany and Zoology, Faculty of Science, Zagazig University, Egypt, between December 2018 and June 2020. Methodology: An analysis of the tested BOs components was done using a Shimadzu GC-9A gas chromatograph. Five sub-lethal concentrations of each plant were prepared (5 replicate/treatment) to evaluate medium lethality against A. ipsilon larvae (20 larvae/replicate). Untreated larvae were used distilled water only as a control. Ten larvae of each treatment were treated with only one LC50 to estimate the effect of different tested BOs on anti-nutritional Activities. Results: The main component of the M. longifolia and A. judaica oil was Piperitone at 39.79 and 37.55%, respectively; whereas the M. hortensis, O. syriacum, and A. santolina oil was Terpinen-4-ol, Thymol, and Fragranyl acetate at 29.82, 31.21, and 25.67%, respectively. According to LC50 of the tested BOs, the toxicity of A. judaica, M. longifolia, O. syriacum, respectively, were the most effective oils, while M. hortensis and A. santolina oils were the least susceptibilities. The more toxic oils reduced food consumption, causing a significant decrease in relative consumption rate (RCR), growth rate (RGR), and efficiency of conversion of ingested food (ECI)/digested (ECD). The previous oils also showed a significant increase in metabolic cost (MC) and anti-feeding activities against A. ipsilon larvae compared to M. hortensis and A. santolina. Conclusion: It is suggested that A. judaica and M. longifolia extracts contain high Piperitone content and could be accepted as toxicants to control A. ipsilon.

Selection of popcorn genotypes tolerant to Spodoptera frugiperda and key traits related to the identification of tolerance

The Spodoptera frugiperda, is one of the most deleterious pests of popcorn and the identification of tolerant genotypes is determinant in breeding programs. The objective of this study was to select popcorn genotypes tolerant to S. frugiperda and the key traits related to the identification of tolerance. The popcorn varieties UEM J1, Composto Márcia, Arachida, Composto Gaúcho and Zapalote Chico (resistant check) were evaluated in a completely randomized design with 100 replications. The experimental unit consisted of one Petri dish, containing plant material and a larva. The following traits were evaluated: larval stage duration (LSt), food intake weight (IW), final larva weight (FW), mean larva weight (MW), feces (F), assimilated (A) and metabolized food weight (M), relative consumption rate (RCR), relative metabolic rate (RMR), relative growth rate (RGR), conversion efficiency of ingested food (CEI), apparent digestibility (AD), conversion efficiency of digested food (CED) and leaf area consumed (LAC). The diagnosis of multicollinearity, analysis of canonical variables, genetic divergence, hierarchical clustering, factor analysis and canonical correspondence analysis were carried out to perform multivariate analysis. After the multicollinearity test, the traits FW, IW, RCR, AD and LAC were maintained for further analysis. Variety Arachida was considered tolerant to S. frugiperda and can be used in the future as a source of favorable alleles to breed tolerant popcorn hybrids. The traits relative consumption rate, apparent digestibility and leaf area consumed were considered key traits in the identification of tolerance against S. frugiperda in popcorn genotypes.

Desperate times call for desperate measures: Short-term use of the common ash tree by gypsy moth larvae (Lepidoptera: Erebidae) under density and starvation stress

Gypsy moth, Lymantria dispar L. (Lepidoptera: Erebidae) feeds on a large number of tree species, while ash, Fraxinus spp. (Lamiales: Oleaceae) species are considered resistant and are only sporadically eaten. To assess the conditions under which late instar gypsy moth larvae (GML) can temporarily use non-host common ash (CA) (F. excelsior L.), and to evaluate their ability to recover from ingestion of this toxic food, we determined the relative growth rate, the relative consumption rate and the amount of produced feces in different laboratory feeding trials. Our report is the first to show that under specific circumstances, the resources acquired after short-term consumption of CA leaves can be utilized for larval growth. We varied the intensity of density and starvation stress prior to feeding on CA leaves. We observed that after moderate stress a group of GML was temporarily capable of coping with CA leaves. Although observed growth and consumption were much lower on CA than on the optimal host oak, Quercus cerris L. (Fagales: Fagaceae), CA-oak-switched larvae showed the ability to recover from short-term use of a toxic non-host foliage. This suggests that feeding on CA might enable GML to survive under conditions of food shortage.

Chemical composition and insecticidal activity Mentha piperita L. essential oil against the cowpea seed beetle Callosobruchus maculatus F. (Coleoptera: Bruchidae)

Antifeedant activity of plant extract from Mentha piperita was tested against the cowpea seed beetle, Callosobruchus maculatus. Dry ground plant was subjected to hydrodistillation using a Clevenger-type apparatus. The resulting oil contained menthone (28.9%), menthol (28.5%), and pulegone (6.9%) as the major compounds. LC50 of M. piperita essential oil was 25.70 μL/L air and mortality increased as the doses of essential oil increased. LT50 values were 3.29, 2.74 and 1.89 h at 100, 200 and 500 μL/L air, respectively. The results of persistence test of oil revealed that essential oil of M. piperita on C. maculatus adults was 5.44 days. It was clear from the repellency index that M. piperita essential oil has strong repellency at 90, 180 and 360 μL/L air concentration. The results showed that M. piperita essential oil has significantly affected the relative growth rate, relative consumption rate and feeding deterrence index of C. maculatus adults and it was concentration-dependent. The efficiency of conversion of ingested food has decreased while the concentrations are not statistically different at 5% level compared to the control group. It seems that essential oil can be used as low-risk insecticides.

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 rm 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.

Eucalyptus dundasii Maiden essential oil, chemical composition and insecticidal values against Rhyzopertha dominica (F.) and Oryzaephilus surinamensis (L.)

The insecticidal effects of Eucalyptus dundasii Maiden essential oil was studied on the adults of the lesser grain borer, Rhyzopertha dominica (F.), and the saw-toothed grain beetle, Oryzaephilus surinamensis (L.). Essential oil was obtained by the hydro-distillation method and essential oil composition was analysed by GC-MS. Chemical analysis indicated that 1,8-cineole (54.15%), p-cymene (12.41%), α-thujene (11.37%), and E-caryophyllene (6.7%) were major constituents. For R. dominica and O. surinamensis, the LC50 of E. dundasii essential oil was 41.69 and 57.92 μl · l-1 of air, respectively. Increasing the concentration of the essential oil and the exposure time, increased mortality. The durability of fumigant toxicity on O. surinamensis adults was higher than on R. dominica adults and was statistically different. Based on the mean of the repellent indexes and the standard deviation, E. dundasii essence was repellent for both insects at 70, 140, and 280 μl · l-1 of air concentrations. Statistical analysis showed that Relative Growth Rate (RGR) in O. surinamensis was higher than in R. dominica, and the Relative Consumption Rate (RCR), the Efficiency of Conversion of Ingested food (ECI), and the Feeding Deterrence Index (FDI) in O. surinamensis was lower than in R. dominica. The many diverse bio-effects of E. dundasii essential oil confirmed that it is a good candidate for management of R. dominica and O. surinamensis

Efficiency of Mentha piperita L. and Mentha pulegium L. essential oils on nutritional indices of Plodia interpunctella Hübner (Lepidoptera: Pyralidae)

Antifeedant activity of plant extracts from <em>Mentha piperita</em> L. and <em>Mentha pulegium</em> L. were tested against the Indian meal moth, <em>Plodia</em> <em>interpunctella</em> (Hübner). The nutritional indices: relative growth rate (RGR), relative consumption rate (RCR), efficiency of conversion of ingested food (ECI) and feeding deterrence index (FDI) were measured for first-instar larvae (15-d old). Treatments were evaluated using a flour disk bioassay in the dark, at 25±1°C and 60±5% R.H. Concentrations of 0, 0.1, 0.5, 0.75, 1, 1.5 and 2 mL/disk were prepared from each essential oil. After 72 h, nutritional indices were calculated. <em>M. piperita</em> oils were more effective than <em>M. pulegium</em> oils, by significantly decreasing the RGR, RCR and FDI. At the highest concentration tested (2 mL/disk), the ECI (9%) was significantly reduced.

AKTIVITAS ANTI MAKAN EKSTRAK DAUN SIRSAK (ANNONA MURICATA L.) DAN PENGARUHNYA TERHADAP INDEKS NUTRISI SERTA TERHADAP STRUKTUR MEMBRAN PERITROFIK LARVA INSTAR V SPODOPTERA LITURA F.

Antifeeding activity of soursop leaf extract (Annona muricata L.) and its effect on nutrition indices and the microscopic structure of peritrophic membrane of the fifth-instar larvae of Spodoptera litura F. were studied. Antifeeding test was conducted by choice method. Discs of caisin leaf were dipped into the ether fraction of soursop leaf extract with concentrations of 0; 0.63; 2.50; and 10.00%. Nutrition indices and peritrophic membrane structure were observed by giving fifth-instar larvae one of the five diets, every group of diet was added to various concentrations of the ether fraction of soursop leaf extract, containing either 0; 0.63; 1.25; 2.50; and 5.00%. The result showed that soursop leaf extract had antifeeding activity at tested concentration 2.50%. Relative consumption rate (RCR), relative growth rate (RGR), and efficiency of conversion of ingested food (ECI) were significantly lower in the case of treated larvae than that of the controls. However the efficiency of conversion of digested food (ECD), approximate digestibility (AD), and peritrophic membrane structure treated with soursop leaf extract were not significantly affected as compared to those in controls.