Effects of applying insecticides to control aphid vectors and cucumber mosaic virus in narrow-leafed lupins Lupinus angustifolius)

1997 ◽  
Vol 37 (1) ◽  
pp. 93 ◽  
Author(s):  
A. M. Bwye ◽  
W. Proudlove ◽  
F. A. Berlandier ◽  
R. A. C. Jones
Keyword(s):  
Grain Yield ◽  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Field Experiments ◽  
Virus Transmission ◽  
Primary Source ◽  
Lupinus Angustifolius ◽  
Current Season ◽  
Infected Seed ◽  
Carbamate Insecticides

Summary. Narrow-leafed lupins (Lupinus angustifolius) were sown in 4 field experiments to investigate the effects of applying organophosphorus and carbamate insecticides on the spread of cucumber mosaic virus (CMV), which is transmitted non-persistently by aphids. The seed sown carried 0 or 5% CMV infection and seed-infected plants were the primary source for subsequent virus transmission by aphids. Virus incidence was gauged by calculating the percentage of plants per plot showing typical current-season CMV symptoms. At final assessment in plots sown with 5% infected seed, recorded CMV incidence was always significantly smaller (up to 3-fold less) when they received sprays of pirimicarb and/or methamidophos every 2 weeks than when they received no insecticide. When single or double strategic sprays of methamidophos or a mixture of pirimicarb/thiometon were applied in late August or early September, they either decreased recorded CMV incidence (up to 2-fold less infection) or had no significant effect on it. Recorded CMV incidence was not significantly diminished by dressing seed with disulfoton or by single- or double-foliar applications of pirimicarb used alone. However, pirimicarb sprays applied every 2 weeks improved grain yield (24% increase), as also did single or double applications of pirimicarb (14%). In one experiment, applications of methamidophos every 2 weeks to plots originally sown with 5% infected seed resulted in increased grain yield (35%) and yields were increased in plots sown with healthy seed whether sprayed every 2 weeks with methamidophos or left unsprayed (42–61%). Pirimicarb suppressed numbers of colonising Acyrthosiphon kondoi and Aphis craccivora to a greater extent than those of Myzus persicae, especially when sprayed every 2 weeks. Single-, double- and sprays of methamidophos every 2 weeks also decreased numbers of Acyrthosiphon kondoi, but had less effect on M. persicae. When different insecticides were tested for their abilities to kill colonising, insecticide-resistant M. persicae, methamidophos was the most effective. This work suggests that single or double strategic foliar sprays of organophosphorus or carbamate insecticides cannot be relied on to control CMV adequately to be recommended for use in increasing grain yields in CMV-infected lupin grain crops.

Effects of sowing seed with different levels of infection, plant density and the growth stage at which plants first develop symptoms on cucumber mosaic-virus infection of narrow-leafed lupins (Lupinus angustifolius)

1994 ◽  
Vol 45 (7) ◽  
pp. 1395 ◽  
Author(s):  
AM Bwye ◽  
RAC Jones ◽  
W Proudlove
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Field Experiments ◽  
Plant Density ◽  
Lupinus Angustifolius ◽  
Virus Spread ◽  
Current Season ◽  
Infected Seed ◽  
High Plant Density ◽  
Sowing Seed

During 1990-92, narrow-leafed lupins (Lupinus angustifolius) cv. Gungurru, were grown in six field experiments in which plots were sown with healthy seed or seed that carried 0.5-5% infection with cucumber mosaic virus (CMV). Seed-infected plants were the primary source for subsequent virus spread by aphids. The rate of CMV spread and the extent of infection in plots depended on the level of infection in the seed sown, the proportion of infected seeds that successfully developed into established plants and the time of arrival and number of aphid vectors. In general, higher seed infection levels, better establishment of seed-infected plants and early aphid arrival favoured greater virus spread, yield loss and infection in the harvested seed. In 1991, in two experiments, late arrival of aphids resulted in minimal CMV spread, no effect on yield and much less infection in the harvested seed than in the seed sown. In the other four experiments, significant yield losses (25-42%) always resulted when seed with 5% or 3% infection was sown. Sowing 1% infected seed resulted in significantly decreased yields in two experiments, while 0.75% and 0.5% infected seed caused significant losses in one experiment (16-19% losses). Yield decreases were due to both fewer seeds being formed and decreased seed size. Levels of infection in harvested seed did not exceed 15%. In a further field experiment in 1991, individual plants that developed CMV symptoms before initiation of flowering or during flowering had significantly smaller yields than those that developed symptoms after flowering had finished. In four field experiments during 1990-91, 10-15% CMV-infected lupin seed was sown at rates of 20-150 kg ha-1 to generate a range of plant densities. The numbers of seed-infected plants were recorded at different times. The extent of loss of seed-infected plants due to shading by neighbouring healthy plants depended on plant density and the time when canopy closure developed. Where no canopy formed there was little or no loss of seed-infected plants, while early canopy formation at high plant density was most effective in removing them. Current-season spread was also decreased by early canopy formation and high plant density, but this effect was smaller when aphids arrived early. This work supports recommendations for management of CMV infection in lupins by sowing seed with low infection (<0.5%) to minimize infection sources, and sowing early at high seeding rates to remove seed-infected plants through improved canopy formation.

Effects of different cultural practices on spread of cucumber mosaic virus in narrow-leafed lupins (Lupinus angustifolius)

1999 ◽  
Vol 50 (6) ◽  
pp. 985 ◽  
Author(s):  
A. M. Bwye ◽  
R. A. C. Jones ◽  
W. Proudlove
Keyword(s):  
Grain Yield ◽  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Field Experiments ◽  
Cultural Practices ◽  
Lupinus Angustifolius ◽  
Row Spacing ◽  
Virus Spread ◽  
Current Season ◽  
Wide Row Spacing

Lupinus angustifolius (narrow-leafed lupin) was sown in 7 field experiments to examine the effects of cultural practices on incidence of cucumber mosaic virus (CMV). The factors investigated were row spacing, banding fertiliser below seed, straw groundover, and tillage. The seed sown carried 5–15% CMV infection. Seed-infected plants were the primary source for subsequent virus spread by aphids. Incidence of seed-infected plants and the extent of virus spread were gauged by counting numbers of lupin plants showing typical seed-borne and current-season CMV symptoms. Due to greater competition with other plants within wide than narrow rows, wide row spacing diminished the survival of seed-infected plants by 46%. Increased plant growth from banding superphosphate below seed did not significantly decrease numbers of seed-infected plants surviving. Straw spread on the soil surface suppressed final CMV incidence by 25–40% and, when applied at different rates, diminished recorded CMV incidence more at 4 than 2 t/ha and least at 1 t/ha. Where there was no straw, CMV incidence increased faster with narrow spacing than wide spacing. Soil disturbance from sowing seed with double discs instead of tynes significantly increased incidences of both seed-borne and current-season infection and diminished grain yield. Neither straw nor row spacing treatments significantly affected grain yield, but the decrease in CMV spread due to straw ground cover significantly increased individual seed weight once and overall yields were greater with straw. Myzus persicae was the main colonising aphid species but Aphis craccivora and Acyrthosiphon kondoi also colonised the lupins. There were significantly fewer colonising M. persicae in plots with 4 t/ha of straw than in those with none. This work suggests that stubble retention, minimum tillage, and wide row spacing should be included as components of an integrated disease management strategy for CMVin L. angustifolius crops.

Predictors of yield of Lupinus angustifolius (cv. Gungurru) seedlots from different sources in Western Australia

1995 ◽  
Vol 35 (6) ◽  
pp. 745
Author(s):  
HL Tapscott ◽  
WA Cowling
Keyword(s):  
Grain Yield ◽  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Seed Size ◽  
Western Australia ◽  
Dry Weight ◽  
Germination Percentage ◽  
Lupinus Angustifolius ◽  
Shoot Dry Weight ◽  
Geographical Source

The growth and yield of 97 seedlots of Gungurm narrow-leafed lupins (Lupinus angustifolius L.) from Western Australia were assessed to identify geographical source or nutritional and physical parameters in the seed that can be used to predict the yield potential of a seedlot. Seedlots were obtained from the 1990 harvest on farms in the south-western cropping region of Western Australia, with up to 7 seedlots from each of 14 crop variety recommendation areas. Each seed lot was assessed for seed size (mean 144 mg), germination percentage (mean 87%), cucumber mosaic virus seed infection (mean 0.11%), and several seed nutrients. Seedlots were sown at 100 kg/ha (without adjusting for germination or seed size) at 4 sites in Western Australia in 1991. Plant density, shoot dry weight (at 6 weeks), and grain yield varied significantly among seedlots, with average grain yield ranging from 951 to 1478 kg/ha (l.s.d. = 240 kg/ha at P = 0.05). Seed size influenced (P<0.001) stand density (r = -0.33) and shoot dry weight (r = 0.58) but not grain yield (r = 0.09, n.s.). No seed nutrient was more than weakly associated with grain yield, nor was there an association of seedlot yield with geographical source of seed. High germination percentage and low cucumber mosaic virus infection were the main predictors of high grain yield in this experiment, but accounted for only 40% of the yield variance among seedlots.

scholarly journals Transmissibility of Cucumber mosaic virus by Aphis gossypii Correlates with Viral Accumulation and Is Affected by the Presence of Its Satellite RNA

2000 ◽  
Vol 90 (10) ◽  
pp. 1068-1072 ◽  
Author(s):  
Fernando Escriu ◽  
Keith L. Perry ◽  
Fernando García-Arenal
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Aphis Gossypii ◽  
Natural Populations ◽  
Virus Transmission ◽  
Negative Effect ◽  
Infected Tomato ◽  
Satellite Rnas ◽  
Viral Accumulation ◽  
Test Plants

Satellite RNAs (satRNAs) are associated with Cucumber mosaic virus (CMV) in tomato, most often causing severe epidemics of necrotic plants, and not associated with specific host symptoms. Laboratory studies on virus transmission by the aphid vector Aphis gossypii were performed to better understand the dynamics of field populations of CMV. The presence of satRNAs correlated with lower concentrations of virus in infected plants and with a decrease in the efficiency of transmission from satRNA-infected plants. Both the concentration of virus in CMV-infected tomato and the efficiency of transmission varied more extensively with nonnecrogenic satRNAs than with necrogenic satRNAs. A negative effect of satRNAs on virus accumulation can account, in part, for a decrease in the field transmission and recovery of CMV + satRNAs. Aphids behaved differently and probed less readily on plants infected with CMV + necrogenic satRNAs compared with plants containing non-necrogenic satRNAs. Aphid-mediated satRNA-free CMV infections were observed in test plants when aphids were fed on source plants containing CMV + nonnecrogenic satRNA; no comparable satRNA-free test plants occurred when aphids were fed on source plants containing necrogenic satRNAs. These results indicate that factors associated with transmission can be a determinant in the evolution of natural populations of CMV and its satRNA.

Lupin grain yields and fertiliser effectiveness are increased by banding superphosphate below the seed

1991 ◽  
Vol 31 (3) ◽  
pp. 357 ◽  
Author(s):  
RJ Jarvis ◽  
MDA Bolland
Keyword(s):  
Grain Yield ◽  
Vegetative Growth ◽  
Field Experiments ◽  
Soil Surface ◽  
Growing Season ◽  
Lupinus Angustifolius ◽  
Grain Yields ◽  
P Content ◽  
Better Than

Five field experiments with lupins (Lupinus angustifolius) measured the effectiveness, for production, of 4 superphosphate placements either: (i) drilled with the seed to a depth of 4 or 5 cm; (ii) applied to the soil surface (topdressed) before sowing; or (iii) banded 2.5-5 cm and 7.5-8 cm below the seed while sowing. Levels of applied phosphate (P) from 0 to 36 kg P/ha were tested. In all experiments lupin grain yield responded to the highest level of superphosphate applied. At this P level, the average grain yield from all trials was 1.16 t/ha for the deepest banded treatment. This was 0.38 t/ha (49%) better than P drilled with the seed, and 0.62 t/ha (115%) better than P topdressed. Relative to superphosphate drilled with the seed and regardless of the lupin cultivar or the phosphate status of the soil, the effectiveness of superphosphate was increased by 10-90% by banding below the seed, and decreased by 30-60% by topdressing. Increasing the levels of superphosphate drilled with the seed generally reduced the density of seedlings and reduced early vegetative growth, probably due to salt or P toxicity. However, during the growing season, the plants treated with high levels of superphosphate recovered, so that eventually yields of dried tops and grain responded to increasing superphosphate drilled with the seed. In each experiment there was a common relationship between yield and P content in lupin tissue, regardless of how the superphosphate was applied, suggesting that lupins responded solely to P, and other factors did not alter yield. We recommend that farmers band superphosphate 5-8 cm below the seed while sowing, rather than continue the present practices of either drilling the fertiliser with the seed, or topdressing it before sowing.

Studies on alfalfa mosaic virus infection of burr medic (Medicago polymorpha) swards: seed-borne infection, persistence, spread and effects on productivity

1992 ◽  
Vol 43 (3) ◽  
pp. 697 ◽  
Author(s):  
RAC Jones ◽  
DA Nicholas
Keyword(s):  
Mosaic Virus ◽  
Seed Yield ◽  
Alfalfa Mosaic Virus ◽  
Primary Source ◽  
Medicago Polymorpha ◽  
Daily Growth ◽  
Infected Seed ◽  
Burr Medic ◽  
Seed Yields ◽  
Healthy Seed

During 1988-90, burr medic (Medicago polymorpha) cvv. Circle Valley, Serena and/or Santiago were grown in field trials in which plots were sown with healthy seed or seed that carried varying levels of infection with alfalfa mosaic virus (AMV). Seed-infected plants were the primary source for subsequent virus spread by aphids. Levels of AMV infection normally reached 80-100% in swards sown with infected seed whether they were mown, grazed or not defoliated, most spread occurring late in the growing season. Infection of harvested seed was often less than in seed sown. However, in self-regenerated grazed swards AMV spread earlier and infection in harvested seed was up to 10 times greater than in seed before regeneration. In two trials sown in 1988, plots were mown or left uncut; AMV infection decreased herbage yields by 13-35% while seed yields were decreased significantly (by 7-30%) in one of the two trails. When one of these trials was cropped with barley in 1989 but allowed to regenerate in 1990 and grazed, herbage yield fell by 5-15% and seed yield by 2-29% due to AMV infection. In a trial sown in 1989 in which some plots were grazed and others not, AMV infection decreased herbage and seed yields by 27-32% and 21-29% respectively. In a similar grazing trial sown in 1990, AMV infection decreased herbage daily growth rates by 16-42% and seed yield sometimes by as much as 32%. Seed harvested from plots sown with infected seed was normally smaller than seed from plots sown with healthy seed. AMV-infected swards were established in 1987, allowed to regenerate in 1988-91 and grazed. With cvv. Circle Valley and Serena, AMV was readily detected each year in foliage and was also found in seeds.

Sign in / Sign up

Export Citation Format

Share Document