A study on common bean cultivars to identify sources of resistance against the black bean aphid,Aphis fabae Scopoli (Hemiptera: Aphididae)

Black bean aphid is an important common bean pest in the world. Aphids damage crops both directly by their feeding and by spreading viruses. Also, they indirectly damages with excretion honeydew and smokes moulds growth through some physiological processes and transmission of viruses. Resistant cultivars application is the main strategy to control Aphis fabae Scopoli. In this experiment, different lines and cultivars were infested with five wingless adult aphids. After 7 and 14?days, plants were evaluated and aphid population was counted and recorded. After 45?days when plants reached to the flowering stage, test was repeated. Result showed that there was a significant difference among cultivars in number of adult aphid in two-leaf stage. Most of the number of adult at the first week in two-leaf stage observed on Goynok cultivar that had significant difference to other lines and cultivars. Number of adults and nymphs among the line and cultivar at flowering stage did not show significant difference. Number of deployed aphids after two weeks was significantly higher than the first week that observed in all cultivars. Totally, the most resistant cultivar was Sayad and the most susceptible cultivar was Goynok.     

Previous infestation of pea aphids Acyrthosiphon pisum on broad bean plants resulted in the increased performance of conspecific nymphs on the plants

Abstract

We studied the effects of previous infestation of broad bean plants by pea aphids Acyrthosiphon pisum on the performance of conspecific nymphs on the plants and the involvement of jasmonic acid (JA)-related defenses. The time needed for newly emerged nymphs to become reproductive adults on broad bean plants previously infested by conspecifics (pre-infested plants) was significantly shorter than on uninfested (control) broad bean plants. The total numbers of nymphs produced by aphids on preinfested and control plants were not significantly different. Preinfested plants produced significantly less endogenous JA than that control plants did. To test the effect of JA decreases, we conducted experiments on the developmental duration of nymphs on broad bean plants treated with JA (JA-treated plants) before infestation. The time needed for nymphs to become reproductive adults on JA treated preinfested broad bean plants was not significantly different from that on JA-treated control plants. The results suggested a possible parental care by pea aphids: the adult aphids manipulated JA-related defenses in broad bean plants that had positive effects for their offspring.     

Characterisation of bird cherry-oat aphid (Rhopalosiphum padi L.) behaviour and aphid host preference in relation to partially resistant and susceptible wheat landraces

The bird cherry-oat aphid (Rhopalosiphum padi L.) is a major pest of wheat (Triticum aestivum L.) and can cause up to 30% yield losses. Heritable plant resistance to aphids is both an economically and ecologically sound method for managing aphids. Here we report how the behaviour and performance of R. padi differs on two resistant, one susceptible wheat landrace and a susceptible elite wheat variety. Feeding behaviour differed among the genotypes, with aphids on resistant lines spending longer in the pathway phase and less time phloem feeding. These behaviours suggest that both inter- and intracellular factors encountered during pathway and phloem feeding phases could be linked to the observed aphid resistance. Locomotion and antennal positioning choice tests also revealed a clear preference for susceptible lines. Although feeding studies revealed differences in the first probe indicating that the resistance factors might also be located in the peripheral layers of the plant tissue, scanning electron microscopy revealed no difference in trichrome length and density on the surface of leaves. Aphids are phloem feeders and limiting the nutrient uptake by the aphids may negatively affect their growth and development as shown here in lower weight and survival of nymphs on resistant genotypes and decreased reproductive potential, with lowest mean numbers of nymphs produced by aphids on W064 (54.8) compared to Solstice (71.9). The results indicate that resistant lines markedly alter the behaviour, reproduction and development potential of R. padi and possess both antixenosis and antibiosis type of resistance.     

Tests for resistance to Aphis fabae in field beans (Viciafaba)

Two lines of Viciafaba were as resistant to Aphis fabae as Rastatt, one of their progenitors, when compared with susceptible control varieties in glasshouse experiments. In short experiments, fewer adult aphids settled on plants of resistant varieties, which subsequently bore smaller total numbers of aphids. In a longer experiment, the aphids multiplied more slowly on the resistant varieties, which survived after susceptible beans had been killed. The bean varieties did not vary in numbers of aphids on the stem or growing point but resistant varieties had markedly smaller proportions of the total on the abaxial surface of the leaves; in particular the smaller veins supported fewer aphids. V. narbonensis was very resistant to A. fabae but was susceptible to Myzus persicae, indicating that its resistance mechanism is distinct from that within V. faba. In infested field trials most of the variation in yield of bean varieties was attributable to the size of A. fabae colonies, and resistant varieties outyielded susceptible varieties. Yields of resistant varieties in the presence of large numbers of aphids were, however, less than those from trials without aphids. In uninfested trials susceptible varieties usually gave the largest yields. The significance of these observations is discussed in relation to policies and methods for breeding for resistance to A. fabae in V. faba.     

Categories of resistance at different growth stages in halt,a winter wheat resistant to the Russian wheat aphid (Homoptera: Aphididae)

This study was designed to categorize the resistance to the Russian wheat aphid, Diuraphis noxia (Mordvilko), resistant hard red winter wheat, Halt, as compared with susceptible wheat, TAM 107, at four different growth stages. Antixenosis was expressed in Halt at growth stage Zadoks 30. Antibiosis in Halt affected fecundity, number of aphids produced per reproductive day, maximum number of nymphs produced in one day, and intrinsic rate of increase. Fecundity was lower on Halt than TAM 107, and more nymphs were produced on both varieties at growth stage 20 than 10 and 40. Fewer nymphs were produced per reproductive day and on maximum production days by aphids reared on Halt than by those reared on TAM 107. The intrinsic rate of increase of Russian wheat aphids reared on Halt was lower than aphids reared on TAM 107. Differences in plant height and plant dry weight did not occur. Chlorosis ratings showed greater damage at the earlier stages in Halt and TAM 107 and significantly more damage in TAM 107 than Halt at growth stages 10, 20, and 30. Leaf rolling occurred on infested plants of TAM 107 at growth stages 10, 20, and 30, but not growth stage 40. Halt plants did not exhibit leaf rolling. The presence of a significant level of tolerance could make Halt compatible with other integrated pest management programs. However, care should be taken with cultivars containing evidence of antixenosis or antibiosis that could cause selective pressure on the Russian wheat aphid, potentially causing biotypes to be produced.     

Determining the host‐plant resistance mechanisms for Mamestra brassicae (Lepidoptera: Noctuidae) pest in cabbage

Six cabbage (Brassica oleracea var. capitata) varieties with different levels of resistance to Mamestra brassicae (Lepidoptera: Noctuidae) were investigated in order to assess whether antibiosis and antixenosis mechanisms are involved in the resistance to this pest or not. Four experiments were conducted to determine the effect of variety and plant ontogeny on larval behaviour, adult oviposition and leaf damages in non‐choice and choice tests. Larval survival, time to development and larval weights differed depending on the varieties and plant stages that we tested. At the pre‐head stage, larval mortality was higher, larvae died faster, time to pupation was shorter, pupae were lighter and the percentage of viable pupae and growth index (GI) values were lower than larvae reared from plants at the head stage. The commercial hybrid ‘Corazón de buey’ and the local variety named ‘BRS0535’ exhibited antibiosis to M. brassicae as they reduced its survival and growth and delayed its development time. In addition, these varieties were the most resistant after artificial infestation in terms of head foliage consumption and number of larvae per plant. Oviposition tests demonstrated that resistance found in ‘Corazón de buey’ and BRS0535 could be also based on antixenosis mechanisms as they resulted in fewer egg batches on plants, whereas BRS0402 could be classified as resistant because M. brassicae larvae showed less preference for it. Thus, resistance to M. brassicae found in cabbage crops may be due to the joint action of several factors involving antibiosis and antixenosis. We found significant differences in the resistance of BRS0535 depending on the plant ontogeny as it loses its resistance while developing. Further studies are required to identify the mechanism of antibiotic resistance which is present in this variety at the pre‐head stage and the changes that occur in plant defence as it grows.     

Characteristics of resistance to the grain aphid Sitobion avenue in winter wheat

Five stocks of winter wheat were resistant to S. avenae in glasshouse screening tests, where resistance was more evident in older than younger plants but different types of resistance were not separated. Antibiosis was measured from the growth and reproduction of caged individual aphids and antixenosis from the settling of adult aphids on detached leaf portions. Cvs Bounty, Rapier and Virtue were resistant due to antibiosis, whilst cv. Kador and line A4501-4E showed antixenosis. These and other differences indicated that these five wheat stocks probably include at least four distinct sources of resistance to S. avenae. The existence of different types of resistance could account for variability in the results of screening tests.     

Detection and analysis of QTLs for resistance to the brown planthopper, Nilaparvata lugens, in a doubled-haploid rice population

 We used a mapping population of 131 doubled-haploid lines, produced from a cross between an improved indica rice variety (IR64) and a traditional japonica variety (Azucena), to detect quantitative trait loci (QTLs) for resistance to the brown planthopper (BPH), Nilaparvata lugens. We evaluated the parents and mapping population with six tests that measure varying combinations of the three basic mechanisms of insect host plant resistance, i.e., antixenosis, antibiosis, and tolerance. To factor-out the effect of the major resistance gene Bph1 from IR64, the screening was done with two BPH populations from Luzon Island, The Philippines, that are almost completely adapted to this gene. A total of seven QTLs associated with resistance were identified, located on 6 of the 12 rice chromosomes. Individual QTLs accounted for between 5.1 and 16.6% of the phenotypic variance. Two QTLs were predominantly associated with a single resistance mechanism: one with antixenosis and one with tolerance. Most of the QTLs were derived from IR64, which has been shown to have a relatively durable level of moderate resistance under field conditions. The results of this study should be useful in transferring this resistance to additional rice varieties. Received: 10 May 1998 / Accepted: 4 June 1998     

Characterization of antibiosis and antixenosis to the soybean aphid (Hemiptera: Aphididae) in several soybean genotypes

The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is an introduced pest of soybean, Glycine max (L.) Merr., in North America, and it can reduce yields by 50%. Since 2000, when A. glycines was first detected in the United States, studies of this insect and possible control methods have been initiated. Plant resistance to this aphid species is one important component of integrated control. Reproduction of A. glycines was compared on 240 soybean entries in a pesticide-free greenhouse. Eleven entries had fewer nymphs produced, compared with the susceptible checks, and these entries were used in follow-up experiments to assess antibiosis and antixenosis. Antibiosis was estimated in true no-choice tests, in which adults were confined individually in double-sided sticky cages stuck to the upper side of leaves. Antixenosis was assessed in choice tests, in which all entries were planted in a single pot. Adult aphids were placed in the center of the pot, and 24 h later the number of adults on each plant was counted. Of the 11 entries evaluated, nine showed a moderate antibiotic effect to A. glycines, and the other two entries (K1639 and Pioneer 95B97) showed not only a strong antibiotic effect but also exhibited antixenosis as a category of resistance to A. glycines. The resistant soybean entries found in this work are potential sources for A. glycines control.     

Effect of parasitism on flight behavior of the soybean aphid, Aphis glycines

Many aphid species possess wingless (apterous) and winged (alate) stages, both of which can harbor parasitoids at various developmental stages. Alates can either be parasitized directly or can bear parasitoids eggs or larvae resulting from prior parasitism of alatoid nymphs. Winged aphids bearing parasitoid eggs or young larvae eventually still engage in long-distance flights, thereby facilitating parasitoid dispersal. This may have a number of important implications for biological control of aphids by parasitoids. In this study, we determined the effect of parasitism by Aphelinus varipes (Hymenoptera: Aphelinidae) on wing development and flight of the soybean aphid, Aphis glycines (Hemiptera: Aphididae). We also quantified the influence of aphid flight distance on subsequent A. varipes development. Parasitism by A. varipes was allowed at different A. glycines developmental stages (i.e., alatoid 3rd and 4th-instar nymphs, alates) and subsequent aphid flight was measured using a computer-monitored flight mill. Only 35% of aphids parasitized as L3 alatoid nymphs produced normal winged adults compared to 100% of L4 alatoids. Flight performance of aphids parasitized as 4th-instar alatoid nymphs 24 or 48 h prior to testing was similar to that of un-parasitized alates of identical age, but declined sharply for alates that had been parasitized as 4th-instar alatoid nymphs 72 and 96 h prior to testing. Flight performance of aphids parasitized as alate adults for 24 h was not significantly different from un-parasitized alates of comparable ages. Flight distance did not affect parasitoid larval or pupal development times, or the percent mummification of parasitized aphids. Our results have implications for natural biological control of A. glycines in Asia and classical biological control of the soybean aphid in North America.     

Effects of brief exposures to low temperature on the development, longevity and fecundity of the grain aphid Sitobion auenae (Hemiptera: Aphididae)

First instar nymphs and adults of the grain aphid Sirobion auenae that had been reared at 10°C and 20°C over a number of generations, were cooled to -5°C and -10°C for 1 h and 6 h and returned to 20°C to assess the effects of brief exposures to low temperatures (cold-pulses) on their survival. rate of development, longevity and fecundity. A strong acclimation response was observed in first instar nymphs, with significantly less mortality in groups reared to 10°C compared to 20°C. Mean development time from first instar to adult was not significantly affected by low temperature exposure at the first nymphal stage. Longevity in all groups cooled as first instars was reduced by the sub-zero cold-pulses, and was also dependent on temperature and exposure time. Acclimated aphids survived longer than non-acclimated individuals. Reproductive rate, in terms of the number of nymphs born per aphid per day, was unaffected by cold stress applied at the first instar stage. Total fecundity was however reduced, being a function of the number and longevity of the survivors. Adult aphids were less cold hardy than nymphs; mortality was higher at -10°C than -5°C increasing with duration of exposure from 1 h to 6 h. Mean fecundity was reduced significantly in aphids cooled at the adult stage, the number of aphids born per day decreasing as the exposure period of the cold-pulse increased, suggesting that low temperature had affected embryogenesis. All the nymphs born to adults surviving exposure to -5°C for 6 h died within 48 h of birth, indicating that low temperature has a pre-natal effect on mortality.     

Settling behaviour and reproductive potential of the green peach aphid Myzus persicae on peach varieties and a related wild Prunus

Discovery in the late seventies of resistance to the green peach aphid Myzus persicae (Sulzer) (Homoptera: Aphididae) in Prunus species was based on screening in the field or in greenhouses with natural aphid populations. Here, we assess the impact of these wild and domesticated peach trees on the behaviour, development, reproductive performance and demography of cloned aphids under controlled light and temperature. Four peach varieties, i.e., Rubira, Weeping Flower Peach, Summergrand and Malo konare and the clone P1908 of the related species Prunus davidiana were tested against the highly susceptible cultivar GF305. Besides a variability in the performance of aphids among experiments, our results showed that (i) distinct mechanisms were involved in the sources of resistance studied and (ii) the ranking of the genotypes on their resistance/susceptibility status remained roughly stable throughout the experiments. Observations on the settling behaviour of first instar nymphs demonstrated antixenosis components in the resistance conferred by Rubira and Weeping Flower Peach. Nymphs began to leave the plants after a short exposure (19–21 h) and no aphid was left after 4 days. Nymphal mortality remained rather low (16%) compared to the repellent effect on aphids of both genotypes. Nymphs disappeared from Weeping Flower Peach significantly earlier than from Rubira. Summergrand, Malo konare and P. davidiana clone P1908 were accepted as host plants by aphids. On P. davidiana, decreased fecundity and intrinsic rate of natural increase (rm=0.20, averaged on all experiments) were clear expression of antibiosis. In addition, the mean length of the mature embryos within the gonads of the females on the day of adult moult was negatively correlated with the total number of embryos, providing evidence that aphids on this genotype lacked sufficient ressources to be directed both towards production and growth of embryos. Compared to the most susceptible cultivar GF305 (rm=0.36), Summergrand (rm=0.26) and Malo konare (rm=0.28) had, to a lesser extent, a negative impact on nymph production and rate of increase.     

Antibiotic resistance in potato cultivars to the aphid Myzus persicae

Commercially-grown potato cultivars were assessed for antibiotic resistance to Myzus persicae in a culture room at 19°C with a 2°C range and a 16 h photoperiod. The resistant rankings obtained were consistent for the following aphid metrics: maturation time, teneral adult weight, embryo complement and the production of nymphs. Intrinsic rates of increase (r_m) correlated with the above parameters of aphid growth and reproduction but this was not always the case for nymphal survival rate. The cultivars Ulster Tarn, Record and Maris Piper were relatively resistant to M. persicae and cultivars Desirée and King Edward were the most susceptible. When the aphid clone or the culture plants were changed there was no significant effect on the relative resistance of the potato cultivars under test. The relationship between the number of embryos in teneral adults and the production of nymphs by aphids was examined by grouping aphids in weight batches. There was a strong relationship between these two variables.     

Reproductive strategy of winged and wingless morphs of the aphids Sitobion avenae and Metopolophium dirhodum

The reproduction of apterous and alate morphs of the aphids Sitobion avenae and Metopolophium dirhodum is compared on the basis of fecundity in 5- and 10-day periods of adult life. Apterae of both species are consistently more fecund than alatae of comparable weight, producing about three more nymphs on average in any 5-day period. The reproductive differences are related to the number and quality of embryos at eclosion and to ovulation rates, both of which in turn appear to be linked to wing-muscle maintenance. These relationships between weight, embryos and reproduction may be used to predict a newly moulted adult aphid's fecundity, a method which may facilitate the assessment of resistance to aphids in new cereal varieties, by obviating lengthy recording of reproduction. The strategies by which alatae of these and other aphid species minimize the difference between their fecundity and that of apterae are discussed.     

The effects of azadirachtin-treated diets on the feeding behaviour and fecundity of the peach-potato aphid,Myzus persicae

Adult apterousMyzus persicae, which had fed for 26 h on diet containing azadirachtin at concentrations of 25–100 ppm, produced nymphs at less than half the rate of aphids on control diets. After 50 h on azadirachtin-treated diets nymph production had virtually ceased. After this period, any nymphs produced by adults that had fed on azadirachtin-treated diets were born dead with undeveloped appendages. Honeydew production on azadirachtin-treated diets was unaffected during the first 26 h period but was approximately three times less than on control diets during the subsequent 24 h period.     

辽宁水稻品种抗灰飞虱鉴定及其抗性机制研究

为探明辽宁地区水稻品种对本地灰飞虱Laodelphax striatellus(Fallén)的抗性水平及其抗虫机制,本研究利用改进的苗期集团鉴定法,以IR36为抗虫对照品种、武育粳3号为感虫对照品种,对42份辽宁地区主栽水稻品种和研究待推广品种进行了水稻苗期对灰飞虱抗性鉴定,并从中选取20份不同抗性水平的品种进行了排趋性和抗生性的测定。结果表明:从42份水稻材料中仅筛选出1份抗虫材料辽优5218,中抗品种11份,其余均为感虫或高感品种。在不同水稻类型中,杂交稻的抗虫性普遍较常规稻强,而从水稻株型上看,抗性品种大多为披散型。抗虫机制研究发现,抗虫品种辽优5218和中抗品种港育129兼具排趋性和抗生性,是非常理想的抗性种质资源,中抗品种港源8号和粳优558具有很强的排趋性,也是较为理想的抗性资源,为抗性机制的深入研究提供了材料。但大部分省内主栽主推品种不具备对灰飞虱的抗性,应引起重视。     

Comparative transmission of bean leaf roll and pea enation mosaic viruses by aphids

Acyrthosiphon pisum was a more efficient vector than Myzus persicae of bean leaf roll virus (BLRV), but the two species transmitted pea enation mosaic virus (PEMV) equally well and much more often than Megoura viciae. M. viciae did not transmit BLRV, and Aphis fabae did not transmit BLRV or PEMV. BLRV and PEMV were transmitted more often by nymphs of A. pisum than by adult apterae or alatae that fed on infected plants only as adults, but both viruses were readily transmitted by adults that had developed on infected plants. The shortest time in which nymphs acquired BLRV was 2 h, and 50 % transmitted after an acquisition period of 4 days. Some nymphs acquired PEMV in 30 min and 50% in 8 h. The shortest time for inoculation of BLRV by adults was 15 min, but some transmitted PEMV in probes lasting less than 1 min. The median latent periods of BLRV and PEMV in aphids fed for 12 h on infected plants were, respectively, 105 and 44 h. Clones of A. pisum differed in their ability to transmit BLRV and PEMV, and efficiency in transmitting the two viruses seemed to be unrelated. Some aphids that fed successively on plants infected with each virus transmitted both viruses, and infectivity with one virus did not seem to affect transmission of the other.     

Acclimatisation in the green spruce aphid, Elatobium abietinum

Thin layer chromatography separation of 80% ethanol extracts of adult Elatobium abietinum revealed the presence of the polyhydric alcohol mannitol in aphids overwintering outdoors but not in aphids kept permanently indoors at 15°C. After 3 days at 15°C no traces of mannitol were left in overwintering aphids. Mean freezing temperatures of outdoor, unfed instar I nymphs were about 4°C lower than those of unfed instar I nymphs produced at 15°C. Mean freezing temperatures of overwintering adults were considerably higher than those of unfed instar I nymphs and showed no changes associated with time at 15°C following transference indoors. Similarly, mean freezing temperatures of Sitka spruce needles transferred to 15°C did not change. It was concluded that, although freezing was mainly avoided by supercooling, the presence of mannitol lowered the true freezing temperature of aphid haemolymph and, consequently, the actual freezing temperatures of nymphs produced under cold conditions. However, the considerable increase in freezing point temperatures caused by imbibition of plant sap masked these acclimatisation changes in feeding aphids.     

Host selection, development, survival, and reproduction of turnip aphid (Homoptera: Aphididae) on green and red cabbage varieties

Host selection, development, survival, and reproduction of the turnip aphid, Lipaphis erysimi (Kaltenbach), on selected green and red cabbage varieties, Brassicae oleracea L. variety capitata, were studied in the laboratory. Although numbers of alate L. erysimi on different varieties varied generally, more alate adults and nymphs were observed on green than on red varieties on day 3; whereas, these differences were not so significant on day 15. There were no significant differences in alate adults on all six varieties on day 15. Numbers of nymphs and apterous adults of L. erysimi varied among the varieties. When mean numbers of those aphids on green varieties were compared with those on red varieties, the green varieties had more nymphs and apterous adults than those on the red varieties. Developmental durations of L. erysimi nymphs also varied among all varieties, and the nymphs fed on green varieties developed longer than those fed on red varieties. Adult longevities on these cabbage varieties were not significantly different; whereas, the adult fecundities were. Survival rates of L. erysimi varied greatly among all varieties, but there are no significant differences between the green and red varieties. Factors that might affect aphid host selection, growth, longevity, fecundity, and survivorship were discussed.     

Feeding behavior of Brevicoryne brassicae in resistant and susceptible collard greens genotypes: interactions among morphological and chemical factors

The cabbage aphid, Brevicoryne brassicae (L.) (Hemiptera: Aphididae), is distributed throughout the tropical and subtropical areas of the world. The main crops attacked by B. brassicae are cabbage, collard greens, broccoli, Brussels sprouts, and cauliflower. To survive the attack of pest insects, plants have evolved various resistance mechanisms that may affect pest feeding behavior. The use of electronic monitoring through EPG (electrical penetration graph) can help characterize and distinguish the resistance mechanisms involved. This study evaluated the feeding behavior of B. brassicae in eight genotypes of collard greens, Brassica oleraceae L. var. acephala (Brassicaceae), exhibiting antixenosis and/or antibiosis resistance to this insect. Possible correlations were established between the glucosinolate levels, the hardness, and the epicuticular wax on the leaves vs. aphid feeding behavior. On the genotypes 22V, 5E, and 27VA, for which many ‘potential drop’ waves were performed, aphid development was slower, indicating antixenosis as resistance type. Aphids on the genotypes 22V and 24X required more time until accessing the phloem, also suggesting antixenosis as resistance category. Genotypes 22V and PE had hard leaves, which also points at antixenosis. Genotypes 20T and HS had higher total wax and wax mg⁻¹. Feeding parameters on ARI and 24X were similar to those observed on HS; antibiosis is likely to be the predominant resistance category of this germplasm. Because HS was considered as a susceptible standard genotype in this study, a higher gluconapin amount indicates that this compound does not influence cabbage aphid feeding behavior. The present study confirms that analysis of the physical and chemical aspects of collard greens genotypes by the EPG technique can provide a useful approach for the study of plant resistance to cabbage aphids.