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1.
This study was conducted to investigate the utility of systematic screening at the genotype level withinSolanum accessions highly resistant to the Colorado potato beetle. Evaluations of clonally replicated genotypes showed that most accessions reported to be uniform when screened as populations contained small but significant variation among genotypes for resistance to oviposition, larvae, and defoliation, differences for numbers of larvae being most common. Adult counts and percentage defoliation were not as useful in evaluating among-genotype variability in beetle resistance. Genotypes ofS. pinnatisectum WRF 343 andS. tarijense PI 473227 were the most uniformly and highly resistant to Colorado potato beetle. Genotypes of S.berthaultii PI 473331,S. chacoense PI 473405, andS. tarijense PI 473336 were moderately to highly resistant, and genotypes ofS. bukasovii PI 473494 andS. canasense PI 230511 were uniformly susceptible to Colorado potato beetle. Nonparametric correlation analyses indicated that number of egg masses, small larvae, large larvae, and defoliation scores were positively correlated, negatively correlated, or not correlated, depending on the species. One generation of selection attempting to segregate resistance and susceptibility in nearly uniform and highly resistantS. pinnatisectum WRF 343 resulted in “divergent” populations that could not be distinguished from each other or the base population. Thus, through genotype (“fine”) screening and selection, we showed that some existing populations are virtually pure for extreme resistance. Use of individuals from such families would make screening breeding populations more efficient, and reduce the risk of losing resistance genes that have non-dominant effects. Fine screening, recurrent selection, and maintenance of such elite populations is recommended as an extension of population-based evaluation usually done by genebanks.  相似文献   

2.
A population of rice brown planthopper(BPH) Nilaparvata lugens collected from a paddy field in Hangzhou was successively reared on susceptible rice Taichung Native 1(TN1) in a laboratory free from insecticides for more than 14 generations. The changes in susceptibility to insecticides and ecological fitness on different resistant rice varieties were monitored in each generation. The resistance ratio to imidacloprid sharply declined with the succession of rearing generations without insecticides from 359.94-fold at F1 to 6.50-fold at F14 compared with the susceptible strain, and the resistance ratio to chlorpyrifos was from 9.90-fold at F1 to 5.94-fold at F14. Nymphal duration and weights of newly hatched female adults were significantly affected by rice variety, generation and their interactions, but nymphal survival was significantly affected by the generation only. The ratio of brachypterous adults in males was affected by the generation and generation × variety interaction, whereas no difference was found in females. Nymphal duration extended with increasing generations, and the female nymphal duration was shorter in the susceptible variety TN1 than those in the resistant varieties IR26 and IR36. In addition, the female adult weight in TN1 was higher than those in IR26 and IR36. These results indicated that the resistance of field BPH population to insecticides was reversed after several generations of no-exposure to insecticides, and the ecological fitness in TN1 was higher than those in IR26 and IR36. These findings suggested the rational and reduced use of insecticides in combination with the manipulation of resistant rice varieties would be effective for BPH management.  相似文献   

3.
The Colorado potato beetle, Leptinotarsa decemlineata Say, is a serious pest of potato, Solanum tuberosum L., worldwide. Leptinotarsa decemlineata has a history of repeated adaptation to insecticides, and exhibits a geographic pattern of decreasing insecticide resistance from east to west in the USA. Imidacloprid is one of the most widely used insecticide in western states. In this study, we measured imidacloprid resistance among larval and adult L. decemlineata from ten locations in the Columbia Basin (southeastern Washington and northeastern Oregon) using topical LD50 bioassays, and compared them to estimates from ten locations in Minnesota and Wisconsin. Larval and adult imidacloprid LD50’s and mean percent mortality were generally lowest in Washington and Oregon, but some sites exhibited reductions in mortality comparable to those observed at some Wisconsin sites. Adult LD50’s suggest L. decemlineata in the Columbia Basin may be evolving in response to selection by neonicotinoid insecticides, but larval data suggest high susceptibility to imidacloprid remains in most populations. Future work should expand resistance monitoring efforts to include more regions in the West and other insecticide modes of action.  相似文献   

4.
An extensive collection of 1527 clones ofS. tuberosum subsp.andigena was screened in 1973 in unreplicated plots to test for resistance to the Colorado potato beetle and potato leafhopper. All clones were susceptible to the beetle. Of 17 clones selected in the 1973 tests for resistance to the potato leafhopper, 7 selections were significantly more resistant than the control (Katahdin) in a replicated experiment in 1974.  相似文献   

5.
A laboratory study was conducted in 1984 to establish base-line data on insecticide tolerance and to detect incipient resistance to representative insecticides within the four major classes of insecticides that are used to control Colorado potato beetles in Idaho. Insecticides tested were aldicarb (a carbamate), endosulfan and DDT (chlorinated hydrocarbons), azinphosmethyl and disulfoton (organophosphates) and fenvalerate (a pyrethroid). Compared with results obtained elsewhere, Idaho populations of Colorado potato beetle proved relatively susceptible to the insecticides tested. However, significant differences were detected among sample populations indicating the potential for insecticide resistance exists.  相似文献   

6.
In laboratory tests conducted to determine the effectiveness of the exotoxin ofBacillus thuringiensis against the Colorado potato beetle,Leptinotarsa decemlineata (Say), applications sprayed on tomato foliage at dilutions ranging from 10?1 through 10?4 killed 90% of the 1st and 2nd stage beetle larvae. As the dosage decreased, the time to achieve this level of mortality increased from 4 to 9 days. Adult beetles were not killed by these treatments; however they did cease feeding. In field tests, the highest dosages ofB. t. sprayed on either tomato or potato plants provided adequate or nearly complete protection when applied weekly. Young larvae that ingested sub-lethal doses developed into adults with atrophied mouthparts and antennae, transformations of the paired parts of the labial palps into an unpaired part, the appearance of a tarsal-like claw on a palp, and malformation of the cranial sclerities.  相似文献   

7.
Reciprocal grafts were done between potato (Solanum tuberosum) and six wildSolanum species known to be resistant to the Colorado potato beetle (Leptinotarsa decemlineata (Say)). Potato or wildSolanum foliage from each reciprocal graft was fed to first instar beetles or adult potato aphids (Macrosiphum euphorbiae (Thomas)). The proportion of second instar larvae after 48 h and survival and fecundity (number of nymphs per female) of the aphids were used to i estimate the resistance level of the foliage. Survival and fecundity of potato aphid were reduced on wildSolanum foliage (except withS. circaeifolium ssp.capsicibaccatum andS. okadae) used as scion or rootstock, but were not different from the control (potato-potato graft) on potato foliage. Development of Colorado potato beetle onSolanum foliage was reduced. In some cases, potato foliage grafted to wildSolanum became resistant to the beetle. Results suggest that a chemical factor or factors providing resistance to Colorado potato beetle are translocated from foliage of some wildSolanum species to potato foliage. They also indicate that mode of resistance to the two insects differs quantitatively or qualitatively.  相似文献   

8.
Colorado potato beetle populations from Idaho were surveyed for resistance to carbofuran, endosulfan, esfenvalerate, and phosmet in a discriminating concentation bioassay of spring emergent and first generation adults. No carbofuran or endosulfan resistance was detected in 29 populations surveyed. Esfenvalerate and phosmet resistance was detected in all potato growing areas of the state. For the same populations, spring adults were more sensitive to phosmet than were first generation adults. Susceptible populations were found in the same regions as resistant populations.  相似文献   

9.
The suspension velocity of the Colorado potato beetle was determined for four stages of its life cycle. Suspension velocities measured using an experimental video technique agreed reasonably well with theoretical values. Suspension velocities for the adults, fourth, third, and second instars were 9.4, 9.5, 7.3, and 5.9 m/sec, respectively. Recent experimental results suggest that a large percentage of adults and large larvae of the Colorado potato beetle are missed during a single pass of commercial field scale vacuum insect collectors. The relatively low suspension velocity of free falling small larvae explain, at least in part, why only 3% of the small larvae fell to the ground.  相似文献   

10.
NewLeaf potatoes could provide substantial ecological and economic benefits to potato growers. A concern with NewLeaf potatoes, however, is that Colorado potato beetle may develop resistance to the Bt endotoxin because of the intense selection pressure imposed by its constant presence in the transgenic crop. Before these cultivars were released, however, entomologists throughout North America conducted biological research needed for a strategy to prevent or delay resistance in Colorado potato beetle. This paper describes the considerations and research behind the proposed strategy. Because NewLeaf potatoes express a relatively constant and high concentration of Bt endotoxin throughout the foliage of each plant, reducing selection for resistance must come from planting standard potatoes as a refuge for susceptible beetles. Avoiding resistance through random mixtures of NewLeaf and standard potatoes was evaluated in laboratory and field studies. The conclusion from this research was that the seed mixture would not provide an effective refuge. The most effective alternative refuge was judged to be a block of standard potatoes planted in the same field as the NewLeaf potatoes. By allowing susceptible beetles to survive in their fields, potato growers might sustain the benefits of very effective controls.  相似文献   

11.
A selection (8380-1) fromSolatium chacoense Bitter (2n=2x=24) accession PI 458310 that synthesizes the leptine glycoalkaloids was compared in growth chambers with tetraploid (2n=4x=48) genotypes derived from tissue culture of 8380-1 leaf expiants for plant growth habit, leaf glycoalkaloid content, and effect on the development of Colorado potato beetle [Leptinotarsa decemlineata (Say)] larvae. The plants of the 4x regenerant genotypes were more vigorous with larger, more oval shaped leaflets than 8380-1 plants. The leaf concentrations of leptines and total glycoalkaloids were significantly lower (about 34%) in the 4x genotypes than in 8380-1. The proportion of leptines in the total glycoalkaloid content was nearly the same (about 80%) in both ploidy groups. In leaf-disk feeding tests, the development of Colorado potato beetle neonate larvae was not significantly different for the 2x and 4x genotypes. Both groups significantly slowed development compared with development on cv. Kennebec leaf disks. The 8380-1 selection and a group of 4x 8380-1 regenerant genotypes are maintained in the Vegetable Laboratory, Beltsville Agricultural Research Center, Beltsville, MD 20705 and are available for distribution.  相似文献   

12.
The cotton whitefly Bemisia tabaci, (Genn.) is an important pest of field crops, vegetables and ornamentals worldwide. Neonicotinoids are considered an important group of insecticides being used against B. tabaci for several years. B. tabaci has developed resistance to some of the compounds of the group. This study was designed to investigate if the selection of B. tabaci with acetamiprid would give a broad-spectrum of cross-resistance and to genetically classify the resistance. At G1 a low level of resistance to acetamiprid, imidacloprid, thiamethoxam, thiacloprid and nitenpyram was observed with resistance ratios of 3-fold, 8-, 9-, 6- and 5-fold, respectively, compared with a laboratory susceptible population. After selection for eight generations with acetamiprid, resistance to acetamiprid increased to 118-fold compared with the laboratory susceptible population. Selection also increased resistance to imidacloprid, thiamethoxam, thiacloprid, nitenpyram, endosulfan and bifenthrin but no change in susceptibility to fipronil was observed. Furthermore resistance in a field population was stable in the absence of acetamiprid selection pressure. Genetic crosses between resistant and susceptible populations indicated autosomal and incompletely recessive resistance. Further genetic analysis suggested that resistance could be controlled by a single factor. The high level of cross-resistance and stability of incomplete resistance in the field population is of some concern. However, lack of cross-resistance between acetamiprid and fipronil or unstable resistance in the resistant population could provide options to use alternative products which could reduce acetamiprid selection pressure.  相似文献   

13.
Test kits were developed to enable growers to assess insecticide resistance in Colorado potato beetle populations. Kits included tests for resistance to: carbofuran (Furadan® 4F), phosmet (Imidan® 50WP), esfenvalerate (Asana® 1.9EC), and a combination of esfenvalerate & piperonyl butoxide (Butacide® 8EC). Tests were petri dishes containing filter paper treated with a discriminating concentration of insecticide (i.e., kills susceptible beetles but not resistant beetles). Discriminating concentrations were determined by testing susceptible and resistant strains of beetle across a range of insecticide concentration. About 200 test kits were distributed during the summer of 1988. Results received indicate: 1) Michigan beetle populations were either susceptible or highly resistant to carbofuran, 2) phosmet resistance was more widespread than previously thought, 3) many populations showed moderate to high levels of resistance to esfenvalerate, and 4) adding piperonyl butoxide reduced resistance to esfenvalerate, in many, but not all populations. Resistance kits help growers determine if insecticide resistance is present in beetle populations (either prior to or after an insecticide application), and also generate data useful to research and extension personnel in documenting the extent and distribution of resistance.  相似文献   

14.
Glycoalkaloids are a class of secondary compounds (nitrogenous, steroidal glycosides), ubiquitously distributed throughout the Solanaceae. Numerous studies (in planta) have shown that certain glycoalkaloids, e.g., α-tomatine, solanocardenine, and leptine, have a negative impact on performance of the Colorado potato beetle,Leptinotarsa decemlineata (Say). However, the presence of other secondary compounds, as well as the nutritional status of the plants used, are additional variables in such experiments. By rearing Colorado potato beetle, from egg to prepupal stage, on a synthetic diet supplemented with the glycoalkaloids α-tomatine, α-chaconine, α-solanine, leptine I and the steroidal aglycone solanidine, we have been able to further establish the effects (ex planta) of these compounds on the Colorado potato beetle. Leptine I displayed a dose-dependent negative activity against the Colorado potato beetle (as measured by larval weight gain and tune to molt), when assayed at 0.31, 0.62 and 1.23 mM concentrations; however, by the fourth stadium no effect was found. When Colorado potato beetle were fed a higher concentration of leptine I (2.4 mM), there was a sustained effect in all stadia. At 2.4 mM, leptine I displayed a greater negative impact on Colorado potato beetle growth and development than did α-tomatine. α-Chaconine at 2.4 mM did not impair Colorado potato beetle performance relative to Colorado potato beetle reared on control diets. α-Chaconine plus α-solanine, at concentrations commonly found inSolanum tuberosum L. foliage (0.6 and 0.3 mM respectively), did not impair Colorado potato beetle performance. The steroidal aglycone solanidine (2.4 mM) had a significant negative impact on Colorado potato beetle performance. Results are discussed in the context of host-plant resistance and insect-plant interactions.  相似文献   

15.
《Crop Protection》1988,7(1):62-65
Three green peach aphid (GPA) strains, Myzus persicae (Sulzer) (Homoptera: Aphididae) obtained from New York, Puerto Rico and Minnesota, were reared on resistant potato hybrid D888-4 and a susceptible cv. Red Pontiac. No significant differences in GPA mortality were observed when aphids were reared on either the resistant or susceptible potato cultivars and later exposed to methamidophos 4EC, pirimicarb 50 WP, azinphos-methyl 2EC or permethrin 2EC. The interaction between the four insecticides × three GPA strains was significant. Of the three aphid strains, those from Minnesota had the lowest susceptibility to permethrin, pirimicarb and azinophos-methyl. No mortality was observed in this GPA strain when tested with azinphosmethyl.  相似文献   

16.
Methods used in breeding and selecting potatoes for resistance to Colorado potato beetle, green peach aphid, potato aphid, and potato leafhopper are reviewed. Sources of resistant germplasm, the nature of resistance, breeding behavior of resistance factors, and methods used to measure resistance are discussed. Specific problems encountered in breeding insect-resistant potatoes are discussed in relation to early-generation selection procedures.  相似文献   

17.
The melon and cotton aphid Aphis gossypii Glover (Hemiptera; Aphididae) is one of the most serious pests worldwide. We surveyed insecticide susceptibility in A. gossypii field populations to 12 insecticides (6 neonicotinoids, 3 pyrethroids and 3 others) to examine resistance ratios. The levels of insecticide resistance were extremely high, especially to neonicotinoids, such as acetamiprid, clothianidin, thiacloprid and imidacloprid. To identify the neonicotinoid resistance mechanisms, we used an imidacloprid-resistant (IMI-R) strain as a model strain. IMI-R showed an extremely high resistance ratio and also cross-resistance to all the test neonicotinoids. However, there was little or no cross-resistance to the other insecticides, including sulfoxaflor. Synergist tests and enzyme activity assays suggested the absence of resistance mechanisms based on enhanced detoxification enzymes, such as cytochrome P450, esterase and glutathione S-transferase. One point mutation was found in the beta1 subunit loop D region of the nicotinic acetylcholine receptor (nAChR) of the IMI-R strain. This R81T point mutation was also found in field populations collected from 5 regions. Therefore, the R81T point mutation was identified as an important mechanism of imidacloprid resistance in A. gossypii.  相似文献   

18.
A refuge of conventional potato plants adjacent to Colorado potato beetle (CPB),Leptinotarsa decemlineata (Say)-resistant,Bt-potato (transgenic) plants may reduce opportunity for the development of tolerance to the resistant plants. The refuge strategy was developed on the basis of data available for CPB recruitment in conventional potato fields. This study was undertaken to provide information on CPB recruitment inBt-transgenic potato fields. A marking experiment was conducted over the 2000 and 2001 crop seasons to determine the relative contributions of beetle populations from fields 10 m, 175 to 300 m, and 1200 to 1280 m distant to the pattern of CPB recruitment (immigration) in aBt-potato field. Season-long CPB recruitment in theBt-potato field decreased with source distance in a manner similar to that previously reported in conventional potato fields. Although marked beetles from the 10-m field plot contributed more to the recruitment than the more distant fields, they contributed only 3.3% and 6.6% of the total beetle sightings in theBt-potato field. Therefore, results suggest that a larger acreage of conventional potato fields at some distance from the resistant crop could replace the adjacent designated refuge. Seasonally, beetles from the overwintering sites provided the first recruits to the resistant field. As their contribution declined, the overwintered beetles from the refuge were recruited until the beginning of the summer population. These results suggest that locating the resistant fields close to active overwintering sites will improve the probability that the refuge strategy will be effective by ensuring the presence of recruits at the very beginning of the crop season. The substantially lower recruitment level obtained for summer than for overwintered CPB in resistant and conventional potato fields highlights the need to reconsider the applicability of the refuge strategy for the summer population.  相似文献   

19.
褐飞虱对吡虫啉敏感性的时空变化及现实遗传力   总被引：12，自引：0，他引：12  
为科学用药,采用稻茎浸渍法测定了我国7省（区）42个田间褐飞虱种群对吡虫啉的敏感性时空变化。结果表明,在1996－2003年,除了1997年广西桂林种群为低水平抗性（6.3倍）外,苏、皖、桂3省13个种群对吡虫啉为敏感至敏感性下降（<5倍）;然而,2005年苏、浙、皖、赣、湘、桂6省（区）16个大田种群对吡虫啉的抗性迅速上升,达高水平至极高水平抗性（79～811倍）;2006年,除江苏通州大田种群的抗性为627倍外,苏、浙、皖、赣、湘、桂、闽7省（区）11个种群的抗性为150～322倍,比2005年有一定程度下降,这可能与暂停使用吡虫啉有关。室内用吡虫啉对褐飞虱筛选18代,其抗性由筛选前的208.3倍上升到筛选后的1110.8倍,抗性现实遗传力（h2）为0.1414。这暗示褐飞虱对吡虫啉产生高水平抗性后,如继续使用吡虫啉防治,其抗性可能会进一步上升。还讨论了稻褐飞虱抗药性的治理策略。  相似文献   

20.
Five insecticide application regimes were evaluated for two years to determine their influence on the development of esfenvalerate resistance by the Colorado potato beetle (CPB),Leptinotarsa decemlineata (Say). These included sequential applications of esfenvalerate; two alternated uses of esfenvalerate, azinphosmethyl, endosulfan, oxamyl, andBacillus thuringiensis or cryolite; an IPM program; and one early season esfenvalerate application. Both CPB adults and first instars were tested for esfenvalerate resistance before and after insecticide applications. The LC50’s in the early 1992 season were correlated with values in the late 1991 season. However, over the winter, esfenvalerate resistance of CPB adults decreased, but was relatively stable for first instars. Esfenvalerate LC50’s late in the season were generally higher than values early in the season. Increases in esfenvalerate LC50’s were correlated with the number of esfenvalerate applications made in these fields during the growing season, with the greatest increase found in the sequential esfenvalerate treatment.  相似文献   

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