Effects of Two Cultivated Brassica spp. on the Development and Performance of Diadegma semiclausum (Hymenoptera: Ichneumonidae) and Cotesia vestalis (Hymenoptera: Braconidae) Parasitizing Plutella xylostella (Lepidoptera: Plutellidae) in Kenya

2019 ◽  
Vol 112 (5) ◽  
pp. 2094-2102 ◽  
Author(s):  
Ruth Kahuthia-Gathu ◽  
Stephen T O Othim
Keyword(s):  
Host Plant ◽  
Plutella Xylostella ◽  
Development Time ◽  
Trophic Levels ◽  
Pupal Weight ◽  
Vegetable Production ◽  
Diadegma Semiclausum ◽  
Cotesia Vestalis ◽  
Positive Effects ◽  
And Performance

AbstractThe diamondback moth (DBM), Plutella xylostella L., is the most destructive pest affecting vegetable production in Kenya and around the world. Parasitoids have shown promising results in lowering the pest populations and damage caused by DBM. However, variations in host plant quality have been reported to have bottom-up effects up to the third and fourth trophic levels. We assessed the effects of two cultivated Brassica varieties (cabbage, Brassica oleracea var. capitata L. cultivar ‘Gloria F1’ and kale, B. oleracea var. acephala L. cultivar ‘Thousand headed’) on the development and performance of the specialist pest P. xylostella and two exotic parasitoids Diadegma semiclausum (Hellen) and Cotesia vestalis (Haliday). The exposed larval period of DBM took about 1.5 d longer on kale than cabbage and the total immature development time of both females and males was significantly longer on kale than cabbage. Higher pupal weight and higher fecundity were recorded on DBM fed on kale. Development time of D. semiclausum and C. vestalis was not affected by the host crop as was the parasitism rate of D. semiclausum. Heavier male pupae and larger adults of D. semiclausum, as well as more fecund adults of C. vestalis, were obtained from hosts fed on cabbage. Larger adults of C. vestalis were obtained from herbivores fed on kale. These results show potentially positive effects of host plant allelochemicals that are detrimental to herbivores while promoting parasitoid development and performance, which can be harnessed for the control of DBM.

scholarly journals Development and reproduction of Diadegma semiclausum (Hymenoptera Ichneumonidae) on diamondback moth Plutella xylostella (Lepidotera Plutellidae)

2008 ◽  
Vol 61 ◽  
pp. 322-327 ◽  
Author(s):  
D. Khatri ◽  
Q. Wang ◽  
X.Z. He
Keyword(s):  
Plutella Xylostella ◽  
Diamondback Moth ◽  
Developmental Period ◽  
Fourth Instar ◽  
Pupal Weight ◽  
Diadegma Semiclausum

This study investigated the development emergence and mating of Diadegma semiclausum Hellen an important parasitoid of diamondback moth in the laboratory at 21 1C and 5060 RH with a photoperiod of 1212 h (lightdark) The parasitoids developmental period was significantly shorter and pupal weight significantly higher if their mothers parasitised the fourth instar larvae of DBM (P

scholarly journals Parameter Biologi dan Demografi Parasitoid Diadegma semiclausum Hellen (Hymenoptera : Ichneumonidae) pada Plutella xylostella L. (Lepidoptera : Plutellidae)

2019 ◽  
Vol 8 (2) ◽  
pp. 156
Author(s):  
NI PUTU NIA KUMARAWATI ◽  
I WAYAN SUPARTHA ◽  
KETUT AYU YULIADHI
Keyword(s):  
Plutella Xylostella ◽  
Generation Time ◽  
Development Time ◽  
Demographic Parameters ◽  
Reproduction Rate ◽  
Intrinsic Growth Rate ◽  
Diadegma Semiclausum ◽  
Immature Development ◽  
Males And Females ◽  
Net Reproduction

Biological and Demographic Parameters of Parasitoid Diadegma semiclausum Hellen (Hymenoptera: Ichneumonidae) on Plutella xylostella L. (Lepidoptera: Plutellidae). Diadegma semiclausum Hellen (Hymenoptera: Ichneumonidae) is one of the parasitoid larvae which attacks Plutella xylostella (Lepidoptera: Plutellidae) effectively. This research was aimed to know the biology of parasitoid D. semiclausum in broccoli. The research was carried out in a laboratory by observing the development of parasitoid, fecundity, longevity the males and females as well as parameters demographic of D. semiclausum. The results showed that immature development time of D. semiclausum parasitoid from egg up to adult the imago was 10.65 ± 0.63 days, with the number of fecundity was 22.9 grains. Longevity of male imago of D. semiclausum was 12.10 ± 0.74 days and imago of females 9.80 ± 1.87 days. Parameters demographic of D. semiclausum showed that net reproduction rate (R0) was 22.11 per generation, intrinsic growth rate (r) was 0.18 per day, limited increased rate (?) was 1.16 individuals per day, generation time (T) was 17.50 day.

Undesirable Effects of Goal Setting on Perceived Fairness, Commitment, and Unethical Behavior

2018 ◽  
Vol 62 (2) ◽  
pp. 97-107 ◽  
Author(s):  
Nina Keith
Keyword(s):  
Goal Setting ◽  
Unethical Behavior ◽  
The United States ◽  
Goal Commitment ◽  
Management Technique ◽  
Long Term Effects ◽  
Perceived Fairness ◽  
Negative Effects ◽  
Positive Effects ◽  
And Performance

Abstract. The positive effects of goal setting on motivation and performance are among the most established findings of industrial–organizational psychology. Accordingly, goal setting is a common management technique. Lately, however, potential negative effects of goal-setting, for example, on unethical behavior, are increasingly being discussed. This research replicates and extends a laboratory experiment conducted in the United States. In one of three goal conditions (do-your-best goals, consistently high goals, increasingly high goals), 101 participants worked on a search task in five rounds. Half of them (transparency yes/no) were informed at the outset about goal development. We did not find the expected effects on unethical behavior but medium-to-large effects on subjective variables: Perceived fairness of goals and goal commitment were least favorable in the increasing-goal condition, particularly in later goal rounds. Results indicate that when designing goal-setting interventions, organizations may consider potential undesirable long-term effects.

Effects of rhizobacteria on the biology and behavior of Plutella xylostella (Lepidoptera: Plutellidae)

2017 ◽  
Vol 43 (2) ◽  
pp. 195
Author(s):  
Robson Thomaz Thuler ◽  
Fernando Henrique Iost Filho ◽  
Hamilton César De Oliveira Charlo ◽  
Sergio Antônio De Bortoli
Keyword(s):  
Plutella Xylostella ◽  
Diamondback Moth ◽  
Insect Behavior ◽  
Control Treatment ◽  
Pupal Weight ◽  
Larval Feeding ◽  
Direct Effects ◽  
Plant Feeding ◽  
Kluyvera Ascorbata ◽  
And Behavior

Plant induced resistance is a tool for integrated pest management, aimed at increasing plant defense against stress, which is compatible with other techniques. Rhizobacteria act in the plant through metabolic changes and may have direct effects on plant-feeding insects. The objective of this study was to determine the effects of cabbage plants inoculated with rhizobacteria on the biology and behavior of diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae). Cabbage seeds inoculated with 12 rhizobacteria strains were sowed in polystyrene trays and later transplanted into the greenhouse. The cabbage plants with sufficient size to support stress were then infested with diamondback moth caterpillars. Later, healthy leaves suffering injuries were collected and taken to the laboratory to feed P. xylostella second instar caterpillars that were evaluated for larval and pupal viability and duration, pupal weight, and sex ratio. The reduction of leaf area was then calculated as a measure of the amount of larval feeding. Non-preference for feeding and oviposition assays were also performed, by comparing the control treatment and plants inoculated with different rhizobacterial strains. Plants inoculated with the strains EN4 of Kluyvera ascorbata and HPF14 of Bacillus thuringiensis negatively affected the biological characteristics of P. xylostella when such traits were evaluated together, without directly affecting the insect behavior.

Effect of leadership styles on organizational commitment and performance in small- and medium-sized enterprises in Iraqi Kurdistan

2020 ◽  
Vol 48 (9) ◽  
pp. 1-12
Author(s):  
Karwan Hamasalih Qadir ◽  
Mehmet Yeşiltaş
Keyword(s):  
Organizational Commitment ◽  
Organizational Performance ◽  
Leadership Styles ◽  
Chief Executive Officers ◽  
Chief Executive ◽  
Mediating Effect ◽  
Positive Effects ◽  
Iraqi Kurdistan ◽  
And Performance ◽  
Executive Officers

Since 2003 the number of small- and medium-sized enterprises (SMEs) has increased exponentially in Iraqi Kurdistan. To facilitate further growth the owners and chief executive officers of these enterprises have sought to improve their leadership skills. This study examined the effect of transactional and transformational leadership styles on organizational commitment and performance in Iraqi Kurdistan SMEs, and the mediating effect of organizational commitment in these relationships. We distributed 530 questionnaires and collected 400 valid responses (75% response rate) from 115 SME owners/chief executive officers and 285 employees. The results demonstrate there were positive effects of both types of leadership style on organizational performance. Further, the significant mediating effect of organizational commitment in both relationships shows the importance of this variable for leader effectiveness among entrepreneurs in Iraqi Kurdistan, and foreign entrepreneurs engaging in new businesses in the region.

scholarly journals Toxicity and Sublethal Effect of Farnesyl Acetate on Diamondback Moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae)

Insects ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 109
Author(s):  
Norazila Yusoff ◽  
Idris Abd Ghani ◽  
Nurul Wahida Othman ◽  
Wan Mohd Aizat ◽  
Maizom Hassan
Keyword(s):  
Plutella Xylostella ◽  
Sublethal Effects ◽  
Diamondback Moth ◽  
Sublethal Effect ◽  
Sublethal Concentration ◽  
Pupal Weight ◽  
Control Group ◽  
Hatching Rate ◽  
Egg Hatching ◽  
Female Ratio

The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is the most important pest of cruciferous vegetables worldwide. In this study, we evaluated the properties of selected farnesyl derivative compounds against P. xylostella. The toxicity and sublethal concentration (LC50) of farnesyl acetate, farnesyl acetone, farnesyl bromide, farnesyl chloride, and hexahydrofarnesyl acetone were investigated for 96 h. The leaf-dip bioassays showed that farnesyl acetate had a high level of toxicity against P. xylostella compared to other tested farnesyl derivatives. The LC50 value was 56.41 mg/L on the second-instar larvae of P. xylostella. Then, the sublethal effects of farnesyl acetate on biological parameters of P. xylostella were assessed. Compared to the control group, the sublethal concentration of farnesyl acetate decreased pupation and emergence rates, pupal weight, fecundity, egg hatching rate, female ratio, and oviposition period. Furthermore, the developmental time of P. xylostella was extended after being exposed to farnesyl acetate. Moreover, the application of farnesyl acetate on P. xylostella induced morphogenetic abnormalities in larval–pupal intermediates, adults that emerged with twisted wings, or complete adults that could not emerge from the cocoon. These results suggested that farnesyl acetate was highly effective against P. xylostella. The sublethal concentration of farnesyl acetate could reduce the population of P. xylostella by increasing abnormal pupal and adults, and by delaying its development period.

scholarly journals Effect of host plant on the life history of the carnation tortrix moth Cacoecimorpha pronubana (Lepidoptera: Tortricidae)

2021 ◽  
pp. 1-7
Author(s):  
Marcin W. Zielonka ◽  
Tom W. Pope ◽  
Simon R. Leather
Keyword(s):  
Life History ◽  
Host Plant ◽  
Plant Species ◽  
Host Plants ◽  
Crop Protection ◽  
Plant Production ◽  
Pupal Weight ◽  
Production Environment ◽  
Host Plant Species ◽  
The Uk

Abstract The carnation tortrix moth, Cacoecimorpha pronubana (Hübner, [1799]) (Lepidoptera: Tortricidae), is one of the most economically important insect species affecting the horticultural industry in the UK. The larvae consume foliage, flowers or fruits, and/or rolls leaves together with silken threads, negatively affecting the growth and/or aesthetics of the crop. In order to understand the polyphagous behaviour of this species within an ornamental crop habitat, we hypothesized that different host plant species affect its life history traits differently. This study investigated the effects of the host plant species on larval and pupal durations and sizes, and fecundity (the number of eggs and the number and size of egg clutches). At 20°C, 60% RH and a 16L:8D photoperiod larvae developed 10, 14, 20 and 36 days faster when reared on Christmas berry, Photinia (Rosaceae), than on cherry laurel, Prunus laurocerasus (Rosaceae), New Zealand broadleaf, Griselinia littoralis (Griseliniaceae), Mexican orange, Choisya ternata (Rutaceae), and firethorn, Pyracantha angustifolia (Rosaceae), respectively. Female pupae were 23.8 mg heavier than male pupae, and pupal weight was significantly correlated with the duration of larval development. The lowest and the highest mean numbers of eggs were produced by females reared on Pyracantha (41) and Photinia (202), respectively. Clutch size differed significantly among moths reared on different host plants, although the total number of eggs did not differ. This study showed that different ornamental host plants affect the development of C. pronubana differently. Improved understanding of the influence of host plant on the moth's life history parameters measured here will help in determining the economic impact that this species may have within the ornamental plant production environment, and may be used in developing more accurate crop protection methodologies within integrated pest management of this insect.

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