scholarly journals Resistance to Beet Armyworm, Hemipterans, and Liriomyza spp. in Lycopersicon Accessions

1993 ◽  
Vol 118 (4) ◽  
pp. 525-530 ◽  
Author(s):  
Sanford D. Eigenbrode ◽  
John T. Trumble ◽  
Richard A. Jones
Keyword(s):  
Lycopersicon Esculentum ◽  
Development Time ◽  
Spodoptera Exigua ◽  
Fruit Size ◽  
Weight Ratio ◽  
Field Trials ◽  
Beet Armyworm ◽  
Breeding Lines ◽  
Clear Identification ◽  
Foliage Weight

Accessions of Lycopersicon esculentum var. cerasiforme (Dun.) A. Gray (cer) and L. pimpinellifolium (Jusl.) Mill. (pimp), sustained significantly less damage to fruit by beet armyworm [Spodoptera exigua (Hiibner)] than standard cultivars and breeding lines of L. esculentum Mill. (esc) under natural infestations in 1990 and 1991 in southern California. The dwarf vine cherry cultivar Tiny Tim also sustained less damage than the standards. Accessions of esc with various monogenic mutations sustained at least as much beet armyworm damage as did standard cultivars. The percentage of fruit damaged was significantly correlated with vine weight, weight per fruit, number of fruit, and the fruit-foliage weight ratio (Pearson's coefficients, respectively: -0.533, 0.450, -0.483, 0.390, n = 37). In laboratory assays, survival of beet armyworm was significantly lower (5% of susceptible& growth rates were significantly lower, and development time was significantly longer on the fruit of resistant `Tiny Tim' and LA 1320 cer than the fruit of 11 other test lines. There were no substantial differences in beet armyworm survival on the foliage of the test lines. In the field trials, there were also significant differences among the test lines in damage by Liriomyza species and hemipteran pests. Lines with genes for increased densities of nonglandular leaf trichomes (especially LA 1663) were generally less damaged by Liriomyza than other lines. Damage by hemipterans was correlated with vine and fruit size, fruit count, and fruit-foliage weight ratio in 1991, but high intraseason variability prevented clear identification of test lines resistant to these pests.

scholarly journals Caterpillar salivary enzymes: "eliciting" a response

2004 ◽  
Vol 85 (1) ◽  
pp. 33-37 ◽  
Author(s):  
Magali Merkx-Jacques ◽  
Jacqueline C. Bede
Keyword(s):  
Artificial Diet ◽  
Spodoptera Exigua ◽  
Induced Defense ◽  
Defense Responses ◽  
Beet Armyworm ◽  
Herbivorous Insect ◽  
Plant Responses ◽  
Plant Defense Responses ◽  
Induced Defense Responses ◽  
Bertha Armyworm

Abstract Plants exhibit remarkable plasticity in their ability to differentiate between herbivorous insect species and subtly adjust their defense responses to target distinct pests. One key mechanism used by plants to recognize herbivorous caterpillars is elicitors present in their oral secretions; however, these elicitors not only cause the induction of plant defenses but recent evidence suggests that they may also suppress plant responses. The absence of “expected changes” in induced defense responses of insect-infested plants has been attributed to hydrogen peroxide produced by caterpillar salivary glucose oxidase (GOX). Activity of this enzyme is variable among caterpillar species; it was detected in two generalist caterpillars, the beet armyworm (Spodoptera exigua) and the bertha armyworm (Mamestra configurata), but not in other generalist or specialist caterpillar species tested. In the beet armyworm, GOX activity fluctuated over larval development with high activity associated with the salivary glands of fourth instars. Larval salivary GOX activity of the beet armyworm and the bertha armyworm was observed to be significantly higher in caterpillars reared on artificial diet as compared with those reared on Medicago truncatula plants. This implies that a factor in the diet is involved in the regulation of caterpillar salivary enzyme activity. Therefore, plant diet may be regulating caterpillar oral elicitors that are involved in the regulation of plant defense responses: our goal is to understand these two processes.

scholarly journals Synthesis and biological activities of two camptothecin derivatives against Spodoptera exigua

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Fulai Yang ◽  
Liping Wang ◽  
Lan Zhang ◽  
Yanning Zhang ◽  
Liangang Mao ◽  
...  
Keyword(s):  
Topoisomerase I ◽  
Spodoptera Exigua ◽  
Insect Pests ◽  
Biological Activities ◽  
Beet Armyworm ◽  
Esterification Reaction ◽  
Contact Toxicity ◽  
Compound A ◽  
High Concentrations ◽  
Insecticidal Activities

AbstractCamptothecin (CPT), a natural alkaloid isolated from Camptotheca acuminata Decne, is found to show potential insecticidal activities with unique action mechanisms by targeting at DNA-topoisomease I (Top1) complex and inducing cell apoptosis. To improve the efficacy against insect pests, two camptothecin (CPT) derivatives were synthesized through introducing two functional groups, 2-nitroaminoimidazoline and 1-chloro-2-isocyanatoethane by esterification reaction. The insecticidal activities of these two derivatives were evaluated at contact toxicity, cytotoxicity and topoisomerase I (Top1) inhibitory activities comparing with CPT and hydroxyl-camptothecin (HCPT). Results showed that compound a, synthesized by introducing 2-nitroaminoimidazoline to CPT, apparently increased contact toxicity to the third larvae of beet armyworm, Spodoptera exigua, and cytotoxicity to IOZCAS-Spex-II cells isolated from S. exigua. However, the inhibition on DNA relaxation activity of Top1 was reduced to less than 5 percentage even at high concentrations (50 and 100 μM). For introducing 1-chloro-2-isocyanatoethane to HCPT, the contact toxicity, cytotoxicity and Top1 inhibitory activity of synthesized compound b were increased significantly compared to CPT and HCPT. These results suggested that both synthesized compounds possessed high efficacy against S. exigua by targeting at Top1 (compound b) or novel mechanism of action (compound a).

scholarly journals Isolation and functional identification of three cuticle protein genes during metamorphosis of the beet armyworm, Spodoptera exigua

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Saad jan ◽  
Sisi Liu ◽  
Muhammad Hafeez ◽  
Xiangmei Zhang ◽  
Farman Ullah Dawar ◽  
...  
Keyword(s):  
Spodoptera Exigua ◽  
Beet Armyworm ◽  
Functional Identification ◽  
Cuticle Protein

scholarly journals Weather based prediction model for beet armyworm (Spodoptera exigua Hubner) in chickpea

2019 ◽  
Vol 40 (1) ◽  
pp. 84-88
Author(s):  
N. Kamakshi ◽  
◽  
D. Sagar ◽  
V. Jayalakshmi ◽  
S. Chander ◽  
...  
Keyword(s):  
Prediction Model ◽  
Spodoptera Exigua ◽  
Beet Armyworm

scholarly journals Flavor Precursor [S-alk(en)yl-L-cysteine sulfoxide] Concentration and Composition in Onion Plant Organs and Predictability of Field White Rot Reaction of Onions

2005 ◽  
Vol 130 (2) ◽  
pp. 196-202 ◽  
Author(s):  
Marilyn H.Y. Hovius ◽  
Irwin L. Goldman ◽  
Kirk L. Parkin
Keyword(s):  
High Performance ◽  
Disease Incidence ◽  
Field Trials ◽  
White Rot ◽  
Individual Plant ◽  
Onion Plant ◽  
Plant Organs ◽  
Breeding Lines ◽  
Sclerotium Cepivorum ◽  
Cysteine Sulfoxide

Breeders have found field screening for white rot (Sclerotium cepivorum Berk.) resistance in onion (Allium cepa L.) to be unreliable since consistently moderate to high disease levels that significantly differentiate cultivars do not occur over field sites and years. The objective was to determine if differences in onion white rot resistance levels were associated with differing S-alk(en)yl-l-cysteine sulfoxide (ACSO) levels. A collection of onion breeding lines and hybrids were evaluated in field trials at six sites in 1999-2001. High performance liquid chromatography was used to analyze ACSOs in onion plant organs. Four main cysteine-sulfoxides exist in Allium L. species: methyl (MCSO), 2-propenyl (2-PeCSO), 1-propenyl (1-PeCSO), and propyl (PCSO). 1-PeCSO was predominant in onion leaves, bulbs, and roots. 2-PeCSO was found in trace amounts in onion leaves and roots. There was significantly more 2-PeCSO and total ACSO (roots only) and 1-PeCSO (roots and bulbs) in accessions that were more susceptible to white rot in the field trials. This is the first report of significant differences in ACSO contents among white rot susceptible and resistant onions. A covariance analysis was used to determine if the ACSO levels that significantly distinguished among accessions could predict field onion white rot reaction. 1-PeCSO from both roots and bulbs was the best predictor of field disease incidence in field sites that had low, moderate, and high disease levels. Although the ACSO concentrations were not assessed on an individual plant basis, breeders may be able to screen onions for resistance to S. cepivorum by comparing onion root or bulb 1-PeCSO levels based on the results from this research. White rot incidence in the field should be higher in those plants whose roots and bulbs have the highest levels of 1-PeCSO.

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