EFFECT OF THE PEA APHID, ACYRTHOSIPHON PISUM (HOMOPTERA: APHIDIDAE), ON COLD-HARDINESS OF ALFALFA

1979 ◽  
Vol 111 (5) ◽  
pp. 635-636 ◽  
Author(s):  
A.M. Harper ◽  
S. Freyman
Keyword(s):  
Cold Hardiness ◽  
Acyrthosiphon Pisum ◽  
Growing Season ◽  
Pea Aphid ◽  
Yield And Quality ◽  
Late Fall ◽  
Southern Alberta ◽  
Pea Aphids

The pea aphid, Acyrthosiphon pisum (Harris), infests alfalfa in southern Alberta and is known to reduce yield and quality of the crop (Harper 1972). From the literature on the pea aphid, recently reviewed by Harper et al. (1978), there do not appear to be any publications on the effect of the pea aphid on cold-hardiness of alfalfa or other host crops. Harper and Lilly (1966), however, found that some aphid-infested plants that were clipped in late fall did not survive the winter. We have observed that numbers of pea aphids often reach high levels on alfalfa in Alberta late in the growing season.

EFFECT OF THE PEA APHID, ACYRTHOSIPHON PISUM (HEMIPTERA (HOMOPTERA): APHIDIDAE), ON YIELD AND QUALITY OF FORAGE ALFALFA

1982 ◽  
Vol 114 (6) ◽  
pp. 485-489 ◽  
Author(s):  
A. M. Harper ◽  
M. S. Kaldy
Keyword(s):  
Dry Matter ◽  
Acyrthosiphon Pisum ◽  
Dry Weight ◽  
Pea Aphid ◽  
Yield And Quality ◽  
Nitrogen Free Extract ◽  
Calcium Magnesium ◽  
The Mean ◽  
Limited Change

AbstractThe pea aphid, Acyrthosiphon pisum (Harris), affected yield by significantly reducing the mean height of aphid-susceptible Grimm alfalfa in a greenhouse experiment by 45%, the height of the longest stem by 35%, the green weight by 38%, the dry weight by 44%, and the fiber by 13%. There was limited change in quality of alfalfa. The percentages of protein, fat, total sugar, reducing sugar, dry matter, and nitrogen-free extract were not significantly different in the infested and non-infested alfalfa. Potassium was significantly lower in the infested plants but they contained more calcium, magnesium, and phosphorus. With the exception of isoleucine the amino acid composition was similar in the infested and non-infested alfalfa.

SEASONAL ABUNDANCE OF THE PEA APHID, ACYRTHOSIPHON PISUM (HOMOPTERA: APHIDIDAE), IN MANITOBA FIELD PEAS

1986 ◽  
Vol 118 (6) ◽  
pp. 601-607 ◽  
Author(s):  
G.A. Maiteki ◽  
R.J. Lamb ◽  
S.T. Ali-Khan
Keyword(s):  
Pisum Sativum ◽  
Acyrthosiphon Pisum ◽  
Pea Aphid ◽  
Seasonal Abundance ◽  
Economic Threshold ◽  
Field Peas ◽  
Pea Aphids

AbstractPea aphids, Acyrthosiphon pisum (Harris), were sampled from 1980 to 1983 in field peas, Pisum sativum (L.), in Manitoba. Sweep and foliage samples were taken in commercial fields and plots. Aphids were found in late May or early June soon after the crop emerged, but populations were low throughout June. Populations increased in July, when the crop was flowering and producing pods, and peaked in the latter half of July or early August in 3 of the 4 years, when pods were maturing. Populations decreased rapidly after the peak, as the plants senesced. In 1980, a drought year, aphid densities were low and the populations peaked in the middle of August. From 1981 to 1983, densities exceeded the economic threshold in all commercial fields and all but one of the plots that were sampled.

scholarly journals The effects of PLA biodegradable and polypropylene nonwoven crop mulches on selected components of tomato grown in the field

2014 ◽  
Vol 26 (2) ◽  
pp. 163-167 ◽  
Author(s):  
Izabela Zawiska ◽  
Piotr Siwek
Keyword(s):  
Ascorbic Acid ◽  
Dry Matter ◽  
Soluble Sugar ◽  
Soluble Sugars ◽  
Growing Season ◽  
Field Studies ◽  
Nitrate Content ◽  
Yield And Quality ◽  
Cotyledon Stage

ABSTRACT The results of two years (2010-2011) of field studies using two types of nonwoven mulches (one biodegradable, polylactic acid PLA 54 g m-2, and traditional polypropylene PP 50 g m-2) on the yield and quality of tomato are presented. Seeds of tomato (‘Mundi’ F1) were sown in a greenhouse, in containers filled with perlite and sand, and then the plants at the cotyledon stage were replanted in multipot trays filled with substrate for vegetable plants. In the last week of May, seedlings were planted on mulches in the field at a spacing of 50 × 100 cm. The mulch was maintained throughout the growing season. A plot that remained unmulched served as the control. Tomatoes were harvested once a week. The fruits were evaluated for L-ascorbic acid, dry matter, soluble sugars and nitrate content. In 2011, the analysis of the plant material showed that the concentration of L-ascorbic acid was about 23% higher in the tomato fruits harvested from plants grown on biodegradable PLA 61 g m-2 mulch in comparison to the control. A similar effect was demonstrated for the soluble sugar concentration in 2011 for both types of nonwovens.

INFLUENCE OF STARVATION ON DEVELOPMENT AND REPRODUCTION IN APTEROUS VIRGINOPARAE OF THE PEA APHID, ACYRTHOSIPHON PISUM (HARRIS) (HOMOPTERA: APHIDIDAE)

1992 ◽  
Vol 124 (1) ◽  
pp. 87-95 ◽  
Author(s):  
K.L. Kouamé ◽  
M. Mackauer
Keyword(s):  
Vicia Faba ◽  
Acyrthosiphon Pisum ◽  
Reproductive Investment ◽  
Dry Weight ◽  
Pea Aphid ◽  
Nutrient Loss ◽  
Adult Weight ◽  
Pea Aphids ◽  
Wet Weight ◽  
Growth Development

AbstractThe influence of nutrient stress on growth, development, and reproduction in apterous virginoparae of the pea aphid, Acyrthosiphon pisum (Harris), was investigated in the laboratory. We tested the hypothesis that species with a high reproductive investment have low resistance to starvation. Aphids in two groups were starved daily from birth for 4 h and 6 h, respectively, and compared with feeding counterparts reared on leaves of broad beans, Vicia faba L. Aphid wet weight increased as an exponential function of age in all groups. Starved aphids had lower adult weight and required longer from birth to parturition than feeding aphids. These effects increased with the length of daily starvation. The number of offspring produced was correlated with adult dry weight. Aphids were unable to compensate, or to compensate completely, for water and nutrient loss resulting from starvation. It is suggested that pea aphids allocate resources first to maintenance and then to reproduction when deprived of food.

COMPARISON OF SWEEP-NET AND STEM-COUNT TECHNIQUES FOR SAMPLING PEA APHIDS IN ALFALFA

1989 ◽  
Vol 24 (3) ◽  
pp. 344-347
Author(s):  
G. David Buntin ◽  
David J. Isenhour
Keyword(s):  
Acyrthosiphon Pisum ◽  
Pea Aphid ◽  
Density Estimates ◽  
Pea Aphids ◽  
Efficient Alternative ◽  
Highly Correlated ◽  
Sweep Net

The accuracy, precision and efficiency of stem-count and sweep-net techniques were compared for sampling the pea aphid, Acyrthosiphon pisum (Harris), in alfalfa. Density estimates by both techniques were highly correlated (r = 0.87). Both techniques were similar in sample precision and efficiency, but stem counts provided more accurate density estimates than the sweep net technique. The stem count technique is an accurate and efficient alternative to the sweep net for sampling pea aphids in alfalfa.

PRODUCTION PRACTICES FOR EARLY MATURING SOYBEANS IN SOUTHERN ALBERTA

1983 ◽  
Vol 63 (3) ◽  
pp. 641-647 ◽  
Author(s):  
S. DUBETZ ◽  
D. J. MAJOR ◽  
R. J. RENNIE
Keyword(s):  
Glycine Max ◽  
Field Capacity ◽  
Rhizobium Japonicum ◽  
Yield And Quality ◽  
Southern Alberta ◽  
Early Maturing ◽  
Glycine Max L ◽  
Production Practices ◽  
Irrigation Requirements

Four experiments were conducted at two locations in southern Alberta, where no indigenous Rhizobium japonicum existed, to determine the effects of seeding dates, fertilizers, irrigation, and method of inoculant placement on the yield and quality of several early-maturing soybean (Glycine max (L.) Merrill) cultivars. Highest yields were obtained when soybeans were seeded during the first half of May. Irrigation requirements varied between years but yields were similar whether soil moisture was depleted to the 6 × 104-Pa or the 3 × 104-Pa level before irrigating to field capacity. Soybean yields increased substantially from N fertilizer when the inoculant was applied to the seed without a sticker. When granular inoculant was banded with the seed there was no response to N, and the yields of inoculated plants were higher than those of plants that were uninoculated and received up to 160 kg N/ha. When properly inoculated, early-maturing cultivars such as King Grain strain X005 and Maple Presto were capable of maturing and producing seed of acceptable yield and quality in southern Alberta.Key words: Cultivars, fertilizer, irrigation, inoculant, Glycine max (L.) Merrill

Escape behaviour of the pea aphid Acyrthosiphon pisum (Harris) in response to alarm pheromone and vibration

1982 ◽  
Vol 60 (10) ◽  
pp. 2245-2252 ◽  
Author(s):  
J. M. Clegg ◽  
C. A. Barlow
Keyword(s):  
Host Plant ◽  
Alarm Pheromone ◽  
Acyrthosiphon Pisum ◽  
Pea Aphid ◽  
Escape Behaviour ◽  
Pea Aphids ◽  
Escape Responses

Pea aphids respond most effectively to the threat of a predator by walking away or dropping from their host plant. Simulating threat by using vibration and alarm pheromone, both separately and together, we found no evidence that escape responses are heritable, nor that individual aphids have characteristic escape behaviours. On the contrary, the amount of alarm pheromone influenced responses: the more pheromone, the more likely an immediate and effective escape. Vibration preceding alarm pheromone greatly increased responsiveness to pheromone, and aphids were more responsive to pheromone after vibration when feeding on stems than when feeding on the undersides of leaves.

Pea aphid, Acyrthosiphon pisum, cornicle ontogeny as an adaptation to differential predation risk

2002 ◽  
Vol 80 (12) ◽  
pp. 2131-2136 ◽  
Author(s):  
Edward B Mondor ◽  
Bernard D Roitberg
Keyword(s):  
Alarm Pheromone ◽  
Acyrthosiphon Pisum ◽  
Harmonia Axyridis ◽  
Inclusive Fitness ◽  
Pea Aphid ◽  
Body Parts ◽  
Anatomical Structures ◽  
Alarm Signaling ◽  
Risk Of Predation ◽  
Pea Aphids

Aphids possess unique anatomical structures called cornicles through which a defensive secretion containing alarm pheromone is often emitted when a predator attacks an aphid. The levels of alarm pheromone in cornicle droplets from the pea aphid, Acyrthosiphon pisum (Harris), vary considerably during development; however, it is not clear how the length of the cornicle changes during ontogeny. The length of the cornicle relative to the lengths of other body structures may have profound effects on aphid defense and alarm signal diffusion. Using previously published morphological measurements of pea aphids and observing interactions between pea aphids and multicolored Asian ladybird beetles, Harmonia axyridis Pallas, it was observed that pea aphid cornicles elongate proportionally more than other body parts during the first four instars, when alarm-pheromone levels have peaked, than during the fifth (adult) instar, when pheromone levels decline. Pea aphids also are more likely to emit cornicle droplets and daub them onto a predator when the cornicles are undergoing such rapid growth. We suggest that because of a high risk of predation, rapid cornicle growth in juveniles has evolved both for individual defense and for the inclusive fitness benefits of alarm signaling.

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