EFFECT OF APPLICATION RATES OF DISULFOTON AND PHORATE, AND OF IRRIGATION ON APHID CONTROL AND RESIDUES IN CANNING PEAS

1967 ◽  
Vol 47 (2) ◽  
pp. 175-180 ◽  
Author(s):  
D. Chisholm ◽  
H. B. Specht

Measurable residues of disulfoton (O, O-diethyl S-2-(ethylthio) ethyl phosphorodithioate) and phorate (O, O-diethyl S-(ethylthiomethyl) phosphorodithioate) were found in pea vines but not in shelled peas 76 days after furrow treatments at time of seeding. Residues of disulfoton were related to application rates. Insecticide treatments satisfactorily controlled pea aphids, Acyrthosiphon pisum (Harris) from plant emergence to harvest. Disulfoton at 1.12-kg/ha active ingredient was as effective as phorate at 2.24 kg/ha. Irrigation, where moisture was not a limiting factor, did not enhance disulfoton or phorate translocation, but by delaying pea maturity it reduced tenderometer readings and yields of shelled peas. Insecticide treatments did not affect yields or tenderometer readings, or produce phytotoxic effects.

1965 ◽  
Vol 45 (6) ◽  
pp. 571-577 ◽  
Author(s):  
H. B. Specht ◽  
D. Chisholm

Furrow applications of Di-syston (O,O-diethyl S-2- (ethylthio)ethyl phosphorodithioate) for control of pea aphids, Acyrthosiphon pisum (Harris), on peas under greenhouse conditions showed that the Di-syston content of the plants reflected the application rates; absorption of Di-syston by the plants was greater on sandy loam than on clay loam; concentrations of Di-syston tended to be highest in the basal third of the pea vines and progressively lower in the middle and top thirds of the plants; slight phytotoxicity occurred on the lower leaves at 4 and 32 lb per acre (4.48 and 35.87 kg/ha) of toxicant but yields were not affected; soil moisture did not affect the uptake of Di-syston in the plant. Differences in uptake may be attributed to differences in the base exchange capacity of the soils.


1990 ◽  
Vol 122 (6) ◽  
pp. 1201-1210 ◽  
Author(s):  
J.J. Soroka ◽  
P.A. Mackay

AbstractPea aphids, Acyrthosiphon pisum (Harris), were sampled weekly or biweekly over the summers of 1985 and 1986 in a total of 15 commercial plantings of Century, Trapper, or Triumph field peas across Manitoba. Pea aphid populations rose more quickly in fields of Trapper than in Century or Triumph fields. The owners of all Trapper fields sampled initiated aerial application of insecticide for pea aphid control; at the time of spraying in 1985, plants in Trapper fields had significantly greater numbers of aphids in sweep samples than such samples from Century or Triumph fields. In 1986, Triumph plants supported greater numbers of aphids than Century or Trapper plants. Triumph plants remained green longer than plants of the other cultivais; in 1985 pea aphid numbers on this cultivar were highest on the last date sampled.Yield components were measured in sprayed and unsprayed plots within the commercial fields. When data were averaged for each cultivar, there were no significant differences in yield per area or in 1000 seed weight between sprayed and unsprayed plots. Data indicated that existing economic thresholds are too low for Trapper peas. However, one of the fields of Trapper peas that we sampled had significantly reduced numbers of pods per plant, yield per square metre, and weight of 1000 seeds in the unsprayed plot; this field had the largest population of pea aphids of any field sampled, with aphid numbers peaking at 48.5 ± 9.2 (SE) per plant lip during pod formation and filling. Significant yield losses also occurred in unsprayed plots of a Triumph field, which had a peak aphid population of 4.8 ± 1.6 per plant stem at pod maturation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yasir Islam ◽  
Farhan Mahmood Shah ◽  
Xu Rubing ◽  
Muhammad Razaq ◽  
Miao Yabo ◽  
...  

AbstractIn the current study, we investigated the functional response of Harmonia axyridis adults and larvae foraging on Acyrthosiphon pisum nymphs at temperatures between 15 and 35 °C. Logistic regression and Roger’s random predator models were employed to determine the type and parameters of the functional response. Harmonia axyridis larvae and adults exhibited Type II functional responses to A. pisum, and warming increased both the predation activity and host aphid control mortality. Female and 4th instar H. axyridis consumed the most aphids. For fourth instar larvae and female H. axyridis adults, the successful attack rates were 0.23 ± 0.014 h−1 and 0.25 ± 0.015 h−1; the handling times were 0.13 ± 0.005 h and 0.16 ± 0.004 h; and the estimated maximum predation rates were 181.28 ± 14.54 and 153.85 ± 4.06, respectively. These findings accentuate the high performance of 4th instar and female H. axyridis and the role of temperature in their efficiency. Further, we discussed such temperature-driven shifts in predation and prey mortality concerning prey-predator foraging interactions towards biological control.


Behaviour ◽  
2021 ◽  
pp. 1-21
Author(s):  
Rosalind K. Humphreys ◽  
Graeme D. Ruxton ◽  
Alison J. Karley

Abstract For herbivorous insects, dropping from the host plant is a commonly-observed antipredator defence. The use of dropping compared to other behaviours and its timing in relation to contact with a predator was explored in both pea aphids (Acyrthosiphon pisum) and potato aphids (Macrosiphum euphorbiae). Pea aphids dropped more frequently in response to ladybird adults (Adalia bipunctata) than lacewing larvae (Chrysoperla carnea). Potato aphids mainly walked away or backed-up in response to both predator types; but they dropped more frequently relative to other non-walking defences when faced with ladybird adults. Contact with a predator was an important influencer of dropping for both species, and most drops occurred from adjacent to the predator. Dropping appears to be a defence adaptively deployed only when the risk of imminent predation is high; factors that increase dropping likelihood include presence of faster-foraging predators such as adult ladybirds, predator proximity, and contact between aphid and predator.


1986 ◽  
Vol 118 (6) ◽  
pp. 601-607 ◽  
Author(s):  
G.A. Maiteki ◽  
R.J. Lamb ◽  
S.T. Ali-Khan

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.


1992 ◽  
Vol 124 (1) ◽  
pp. 87-95 ◽  
Author(s):  
K.L. Kouamé ◽  
M. Mackauer

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.


1989 ◽  
Vol 24 (3) ◽  
pp. 344-347
Author(s):  
G. David Buntin ◽  
David J. Isenhour

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.


2003 ◽  
Vol 82 (3) ◽  
pp. 152-161 ◽  
Author(s):  
Atsushi Nakabachi ◽  
Hajime Ishikawa ◽  
Toshiaki Kudo

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