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S. D. Kindler

Bio: S. D. Kindler is an academic researcher. The author has contributed to research in topics: Empoasca fabae & Leafhopper. The author has an hindex of 2, co-authored 3 publications receiving 42 citations.

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TL;DR: Alfalfa clones representing a broad range of resistance to the yellowing caused by Empoasca fabae (Harris), were evaluated to determine the interrelationship between resistance to yellowing and changes in the yield and in the quality of forage.
Abstract: Twelve alfalfa clones representing a broad range of resistance to the yellowing caused by Empoasca fabae (Harris), were evaluated to determine the interrelationship between resistance to yellowing and changes in the yield and in the quality of forage. Some clones had high levels of resistance to yellowing despite large populations of leafhoppers, but when infestations were moderate to heavy, all clones had substantially reduced total growth, yield of forage, and quantity of such important qualitative components as carotene and protein. The changes in yield and quality of individual clones compared with uninfested counterparts were generally less for resistant than for susceptible clones. Digestible dry matter (dry matter disappearance) was affected little by potato leafhoppers, but none of the clones had measurable resistance to stunting. Infested plants consistently had much higher dry-matter content than uninfested plants, which tends to negate estimates of yield based on plant length and green weight.

25 citations

Journal ArticleDOI
TL;DR: When pea Aphids, Acyrthosiphon pisum (Harris), and spotted alfalfa aphids, Therioaphis maculata (Buckton), were introduced into field cages containing aphid-re-sistant (Dawson or KS-IO), both species increased until harvest on all varieties, but at harvest, fewer were present on resistant than on susceptible varieties.
Abstract: When pea aphids, Acyrthosiphon pisum (Harris), and spotted alfalfa aphids, Therioaphis maculata (Buckton), were introduced into field cages containing aphid-re-sistant (Dawson or KS-IO) and aphid-susceptible (‘Ranger’ or ‘Vernal’) varieties of alfalfa, both species increased until harvest on all varieties, but at harvest, fewer were present on resistant than on susceptible varieties. Also the contents of protein, carotene, and digestible dry matter (dry matter disappearance) in the dry matter of the susceptible varieties were generally reduced more by both aphids than that of the resistant varieties. Over 2 years, pea aphids reduced the yield of dry matter from resistant and susceptible varieties by an average 23 and 48%, respectively; spotted alfalfa aphids reduced yields of the same varieties by an average of 19 and 38%. The 2-year average reduction in yield of chemical constituents caused by pea aphids was 26% for the resistant varieties and 57% for the susceptible varieties; that caused by spotted alfalfa aphids was 24 and 48%, respectively. Stand losses were low the spring following the artificial infestation the preceding year. However, pea aphids reduced stands of resistant and susceptible varieties by an average 2 and 6%, respectively; spotted alfalfa aphids reduced stands of the same varieties by an average 0 and 6%.

16 citations


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Journal ArticleDOI
TL;DR: Virulence to aphid resistance genes of plants occurs in 17 aphid species--more than half of all arthropod biotypes demonstrating virulence, highlighting the need to identify new sources of resistance of diverse sequence and function in order to delay or prevent biotype development.
Abstract: Aphids damage major world food and fiber crops through direct feeding and transmission of plant viruses. Fortunately, the development of many aphid-resistant crop plants has provided both ecological and economic benefits to food production. Plant characters governing aphid host selection often dictate eventual plant resistance or susceptibility to aphid herbivory, and these phenotypic characters have been successfully used to map aphid resistance genes. Aphid resistance is often inherited as a dominant trait, but is also polygenic and inherited as recessive or incompletely dominant traits. Most aphid-resistant cultivars exhibit constitutively expressed defenses, but some cultivars exhibit dramatic aphid-induced responses, resulting in the overexpression of large ensembles of putative aphid resistance genes. Two aphid resistance genes have been cloned. Mi-1.2, an NBS-LRR gene from wild tomato, confers resistance to potato aphid and three Meloidogyne root-knot nematode species, and Vat, an NBS-LRR gene from melon, controls resistance to the cotton/melon aphid and to some viruses. Virulence to aphid resistance genes of plants occurs in 17 aphid species--more than half of all arthropod biotypes demonstrating virulence. The continual appearance of aphid virulence underscores the need to identify new sources of resistance of diverse sequence and function in order to delay or prevent biotype development.

120 citations

01 Jan 1994
TL;DR: A new model for assessing tolerance to the greenbug, Schizaphis graminum (Hendani), in sorghum was developed, independent of antibiosis effects and is a combination of three different techniques, with the greatest importance placed on the slope described by the relationship between infested and control seedling weights at the end of the experiment.
Abstract: Selected papers dealing with the tolerance mechanism of host plant resistance to aphid species in crop plants have been critically reviewed herein. Some of the researchers employed techniques that were incorrect.1y assumed to be measuring tolerance. In other research, no attempt was made to separate tolerance and antibiosis components, while in other research the effect of variation in plant biomass on tolerance expressed among cultivars was not considered. After testing a series of analysis of covariance models, as well as several other techniques, a new model for assessing tolerance to the greenbug, Schizaphis graminum (Hendani), in sorghum was developed. This new model is independent of antibiosis effects and is a combination of three different techniques, with the greatest importance placed on the slope described by the relationship between infested and control seedling weights at the end of the experiment.

71 citations

Journal ArticleDOI
TL;DR: Observations strongly support Medler's (1941) hypothesis that hopperburn is caused by a substance in the insect's saliva that induces plant cells to enlarge and block the phloem.
Abstract: The feeding behaviors and salivary deposits of the potato leafhopper, Empoasca fabae (Harris), on stems of a susceptible cultivar of alfalfa (Medicago sativa, L.) were studied in relation to the cellular damage and initiation of hopperburn they cause. An AC electronic monitoring system (EMS) was used to quantify the number and duration of probes made on alfalfa stems. Light and electron microscopy were then used to examine the effects of these probes. Most probes were short in duration as determined by EMS and comprised primarily of multiple-cell laceration behavior (represented by the Ia waveform). Probes containing still-stylet ingestion behavior (represented by the Ic waveform) were longer in duration and occurred less frequently. There was a close correspondence between the number of probes containing the Ic waveform and number of salivary deposits. Histological examinations of the stems revealed six types of salivary deposits but only one of these resembled the solid, distinct (or ‘true’) salivary sheaths characteristic of sheath-feeders. Less than 25% of E. fabae probes left any salivary deposit, and only 1% left true sheaths. Therefore, it seems unlikely that these deposits could physically block the phloem to cause hopperburn. Cellular disruptions, such as abnormally divided and enlarged cells, were found in the vascular cambium and phloem, as well as other tissues. Enlarged vascular cambial cells appeared to crush the phloem cells, and thus probably caused hopperburn. This microscopic damage was initiated by vigorous, active probing, along with the copious watery saliva that is secreted during the behavior represented by Ia. These observations strongly support Medler's (1941) hypothesis that hopperburn is caused by a substance in the insect's saliva that induces plant cells to enlarge and block the phloem. Resume Depots salivaires et degâts sur tiges de luzerne associes au comportement specifique de sondage d‘Empoasca fabae Le comportement alimentaire et les depots salivaires d'E. fabae Harris ont ete examines en relation avec les degâts cellulaires sur tiges de cultivars sensibles de Medicago saliva. Un systeme de controle electronique AC (EMS) a ete utilise pour quantifier le nombre et la duree des sondages dans les tiges de luzerne. Les microscopies optique et electronique ont permis d'examiner les effets de ces sondages. EMS a montre que la majorite des sondages etaient brefs (1 a 2 min) et commencait par la laceration multiple de cellules (revele par un onde Ia). Les sondages comprenant un comportement d'ingestion avec immobilisation des stylets (revele par une onde Ic) sont plus longs et moins frequents. Il y a une bonne correspondance entre le nombre de sondages contenant un onde Ic et le nombre de depots salivaires. L'association des sondages et des depots salivaires montre que la duree du sondage etait plus liee a la solidite des depots salivaires que la duree des ondes individuelles. L'examen histologique des tiges a revele 6 types de depots salivaires, mais seul l'un d'entre eux ressemblait a celui donnant la gaine sonde, individualisee (ou veritable) gaine salivaire caracteristique des consommateurs avec gaines salivaires. Moins de 25% des sondages d'E. fabae laissent un depot et seulement 1% laisse une veritable gaine. Ainsi, il semble improbable que ces depots puissent bloquer le phloeme et provoquer la brulure des ciccadeles. Des degâts cellulaires, tels que divisions anormales et cellules hypertrophiees, ont ete observes dans la cambium vasculaire et dans le phloeme, ainsi que dans d'autres tissus. Dans des tissus fortement abimes, le phloeme est completement desorganise et contient des cellules ratalinees et affaissees. Des cellules vasculaires cambiales hypcrtrophiees paraissaient aplatir les cellules du phloeme, et ainsi interferer avec la translocation des photosynthetats. Les degâts microscopiques sont produits par les sondages actifs et vigoureux, associes a la copieuse detrempe salivaire secretee pendant le comportcment representer par Ia. Ces observations appuient fortement l'hypothese de Medler (1941) suivant laquelle la brulure des ciccadeles est provoquee par une substance de la salive de l'insecte qui induit l'hypertrophie cellulaire et bloque le phloeme.

52 citations

Journal ArticleDOI
TL;DR: Both salivation and mechanical wounding by leafhopper stylets are probably necessary to cause hopperburn‐associated anatomical changes to vascular tissue in stems of alfalfa, and this conclusion supports the hypothesis thatHopperburn is a saliva‐enhanced wound response.
Abstract: Studies were conducted to separate the salivary and mechanical aspects of probing damage by the potato leafhopper, Empoasca fabae (Harris) (Homoptera: Cicadellidae), to stem vascular tissue of alfalfa, Medicago sativa L. Implantation of salivary gland tissue or fed-upon artificial diet under the stem epidermis yielded no evidence, three days later, of hopperburn-associated, anatomical changes. Mechanical puncturing of stems with implements approximating the size and shape of leafhopper stylets caused some anatomical changes, three days later, similar to those underlying hopperburn, i.e. tracks of necrosis, chlorosis, cell enlargement, and cell division. These changes, however, were much less severe than those observed in tissues three days after potato leafhopper probing. In contrast, puncturing through salivary gland or Malpighian tubule tissues produced extreme hyperplasia and other symptoms of wounding in cells near the puncture. This was similar to but more severe than effects from leafhopper probing, and was probably caused by leafhopper structural tissues or larger amounts of saliva being conveyed into the plant than normally occurs during leafhopper probing. We conclude that both salivation and mechanical wounding by leafhopper stylets are probably necessary to cause hopperburn-associated anatomical changes to vascular tissue in stems of alfalfa. This conclusion supports our hypothesis that hopperburn is a saliva-enhanced wound response.

45 citations