ECONOMIC INJURY LEVELS OF THE TARNISHED PLANT BUG, LYGUS LINEOLARIS (HEMIPTERA (HETEROPTERA): MIRIDAE), ON GREEN BEANS IN QUEBEC

1980 ◽  
Vol 112 (3) ◽  
pp. 306-310 ◽  
Author(s):  
R. K. Stewart ◽  
A. R. Khattat

AbstractCaged microplots of “Contender” green beans, Phaseolus vulgaris L., were artificially infested with various densities of Lygus lineolaris (Palisot de Beauvois) to determine the effect of feeding on yield and quality, and to establish economic injury levels. Plants infested at bloom or pod set stage were more severely injured than those infested at the flower bud stage. Higher infestation levels reduced crop yield, but the percentage of crude protein in bean seeds was not affected. Based on 1975 crop values and chemical control costs, economic injury levels ranged between 0.3 and 4.4 insects/10 plants depending on crop use, chemical control, and plant stage infested.

1980 ◽  
Vol 112 (3) ◽  
pp. 301-305 ◽  
Author(s):  
R. K. Stewart ◽  
A. R. Khattat

AbstractAdult and nymphal populations of the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), on “Contender” green beans, Phaseolus vulgaris L., were sampled during the summers of 1971–1972. Sweep net and D-Vac® suction apparatus samples were taken concurrently, and both estimates were compared by regression analysis.The tarnished plant bug reached levels above the economic injury levels for both early and late crops in 1971–1972. The economic threshold was determined as 0.5 insect/10 plants below the economic injury level.


2020 ◽  
Vol 20 (4) ◽  
Author(s):  
Maribel Portilla

Abstract A laboratory, diet-overlay pesticide bioassay was developed using a susceptible population of the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), to study its susceptibility to neonicotinoid, sulfoxamine, organophosphate, and pyrethroid insecticides (thiamethoxam, sulfoxaflor, acephate, and permethrin, respectively). The diet-overlay bioassay was compared to the traditional glass-vial surface residue bioassay. We measured LC50 values by feeding tarnished plant bug adults known doses of insecticides dispensed on top of diet in a 10% solution of honey water for thiamethoxam and 10% acetone in water solutions for permethrin, acephate, and sulfoxaflor. Both the diet-overlay and glass-vial bioassays used dose-response (mortality) regression lines to calculate LC50 values for each insecticide at 6-, 24-, 48-, and 72-h post-exposure. Data variability from the glass-vial bioassay was higher for permethrin, sulfoxaflor, and thiamethoxam than the diet-overlay bioassay, for all evaluation times. In contrast, there was lower variability among replicates to acephate in the glass-vial assay compared to the diet-overlay assay. Control mortalities observed on diet-overlay bioassay were lower (0–5%) than those observed on the glass-vial bioassay (4–27%). The use of green beans, floral-foam, rolling glass vials, and insect handling made the existing standard method tedious to manipulate and difficult to handle large numbers of individuals. The nonautoclaved solid diet provides an opportunity to significantly reduce cost and variability associated with procedures of other bioassay methods. In general, the baseline data provide a basis for future comparison to determine changes in resistance over time.


1987 ◽  
Vol 27 (1) ◽  
pp. 55 ◽  
Author(s):  
RH Slarke ◽  
WK Mason

At Kyabram, Victoria, the effects of growth stage at cutting on dry matter (DM) yield and quality of lucerne was determined during the warm season haymaking period for cultivars with contrasting winter dormancy characteristics. Growth stages at cutting were pre-flower bud, flower-bud, 10% bloom and full bloom. Cultivars were winter non-dormant CUF 101 and Pioneer Brand 572, semi-winter dormant Pioneer Brand 581 and winter dormant Pioneer Brand 545. Cultivar responses or interactions between cultivar and growth stage at cutting were not significant (P>0.05) for dry matter yield, crude protein or in vitro digestibility. Cutting of the pre-flower bud stage, compared with cutting at the 10% bloom stage, reduced DM yield by 18% (16.4 v. 13.5 t/ha), but increased crude protein content of the lucerne from 19.3 to 24%. The total protein yield per hectare was not affected by cutting stages from pre-flower bud stage to 10% bloom. Cutting lucerne at the flower bud stage rather than at 10% bloom gave increased protein content and digestibility with only a moderate yield decline. However, more frequent cutting was unsatisfactory as it decreased the density of the stand and increased the proportion of weeds and so could not be recommended.


Insects ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1072
Author(s):  
Scott H. Graham ◽  
Angus L. Catchot ◽  
Jeffrey Gore ◽  
Donald R. Cook ◽  
Darrin Dodds

The tarnished plant bug (Lygus lineolaris Palisot de Beauvois) is the dominant insect pest of cotton (Gossypium hirsutum L.) in the Mid-South Cotton Belt. This is partly due to the fact that this pest has developed resistance to most insecticides used for control. Laboratory experiments were conducted during 2014 and 2015 to study the behavioral response of tarnished plant bug nymphs to several classes of insecticides. Twenty third-instar nymphs were placed in individual dishes divided into four quadrants with five green bean pieces in each quadrant (10 treated and 10 untreated green beans in each dish). Dishes were checked at 1, 4, 8, and 24 h. Tarnished plant bug nymphs appeared to avoid green beans treated with IGR, pyrethroid, organophosphate, or carbamate insecticides, while there appeared to be an attraction to green bean pieces treated with sulfoxamine and pyridine carboxamide insecticides. No relationship was observed with neonicotinoid insecticides within 24 h.


2021 ◽  
Vol 13 (15) ◽  
pp. 8247
Author(s):  
Dimitrios N. Vlachostergios ◽  
Christos Noulas ◽  
Anastasia Kargiotidou ◽  
Dimitrios Baxevanos ◽  
Evangelia Tigka ◽  
...  

Lentil is a versatile and profitable pulse crop with high nutritional food and feed values. The objectives of the study were to determine suitable locations for high yield and quality in terms of production and/or breeding, and to identify promising genotypes. For this reason, five lentil genotypes were evaluated in a multi-location network consisting of ten diverse sites for two consecutive growing seasons, for seed yield (SY), other agronomic traits, crude protein (CP), cooking time (CT) and crude protein yield (CPY). A significant diversification and specialization of the locations was identified with regards to SY, CP, CT and CPY. Different locations showed optimal values for each trait. Locations E4 and E3, followed by E10, were “ideal” for SY; locations E1, E3 and E7 were ideal for high CP; and the “ideal” locations for CT were E3 and E5, followed by E2. Therefore, the scope of the cultivation determined the optimum locations for lentil cultivation. The GGE-biplot analysis revealed different discriminating abilities and representativeness among the locations for the identification of the most productive and stable genotypes. Location E3 (Orestiada, Region of Thrace) was recognized as being optimal for lentil breeding, as it was the “ideal” or close to “ideal” for the selection of superior genotypes for SY, CP, CT and CPY. Adaptable genotypes (cv. Dimitra, Samos) showed a high SY along with excellent values for CP, CT and CPY, and are suggested either for cultivation in many regions or to be exploited in breeding programs.


2018 ◽  
Vol 34 (3) ◽  
pp. 345-353 ◽  
Author(s):  
Violeta Mandic ◽  
Zorica Bijelic ◽  
Vesna Krnjaja ◽  
Aleksandar Simic ◽  
Maja Petricevic ◽  
...  

Maize is the very important silage source in the world. Timely harvesting ensure high maize forage yield and quality. Therefore, the study focused on the effects of four harvesting times (starting at the 12 August every 7 days) on yield and qualitative parameters of forage green mass of maize hybrid ZP 677. The experiment was set in Vojvodina Province, Serbia, during the 2013 and 2014 growing seasons. Plant height, stem diameter, number of leaves per plant, ear percentage, forage yield, dry matter content and crude protein content were higher, while stem percentage was lower in 2014 with favorable climatic condition. Forage yield, crude protein content, ADF and NDF decreased, while dry matter content significantly increased with delay in harvesting. The maize hybrid should be harvested when the milk line is three-quarter of the way down the grain that is in the third decade of August.


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