Vertical Distribution of Black Vine Weevil (Coleoptera: Curculionidae) Immatures and Infection by Entomogenous Nematodes in Soil Columns and Field Soil

1993 ◽  
Vol 86 (2) ◽  
pp. 340-347 ◽  
Author(s):  
James L. Hanula
Keyword(s):  
Vertical Distribution ◽  
Field Soil ◽  
Soil Columns ◽  
Black Vine Weevil

scholarly journals Vertical Distribution of Heterodera schachtii under Susceptible, Resistant, or Tolerant Sugar Beet Cultivars

Plant Disease ◽  
2013 ◽  
Vol 97 (1) ◽  
pp. 101-106 ◽  
Author(s):  
Andreas Westphal
Keyword(s):  
Sugar Beet ◽  
Vertical Distribution ◽  
Cover Crops ◽  
Heterodera Schachtii ◽  
Root Penetration ◽  
Susceptible Cultivar ◽  
Field Soil ◽  
Sugar Beets ◽  
Naturally Occurring ◽  
White Sugar

Heterodera schachtii is managed by rotation with non-hosts, resistant cover crops, and resistant and tolerant sugar beet cultivars. Microplots 60 cm deep and 30 cm in diameter containing steamed field soil were (i) noninfested or infested with 550 H. schachtii eggs per 100 g at (ii) 0 to 60 cm, (iii) 0 to 30 cm or (iv) 30 to 60 cm in depth. Plots were planted to susceptible, resistant, and tolerant sugar beets. Five weeks later, the sugar beet canopy was largest in condition i, smallest in condition ii, and intermediate in conditions iii and iv. White sugar yield (WSY) was highest in condition i, second in condition iv, lowest in condition ii, and intermediate in condition iii. Cultivar-specific final nematode numbers were independent of the level of infestation. In two experiments utilizing 1-m2 microplots, naturally occurring H. schachtii populations were suppressed with fosthiazate at depth layers in reverse to those infested in the first experiment, and planted to susceptible, resistant, and tolerant sugar beets. In one experiment, WSY was highest in soil treated with fosthiazate at 0 to 60 cm in depth, lowest in nontreated, unaffected in soil treated at 30 to 60 cm in depth, and somewhat lower in soil treated at 0 to 30 cm in depth. In all cultivars, early root penetration predicted canopy diameter; only in the susceptible cultivar did the canopy diameter predict WSY. Deep-occurring H. schachtii can impact productivity in sugar beet cropping.

Adsorption, Mobility, and Degradation of Cyanazine and Diuron in Soils

Weed Science ◽  
1977 ◽  
Vol 25 (5) ◽  
pp. 401-406 ◽  
Author(s):  
J.T. Majka ◽  
T.L. Lavy
Keyword(s):  
Adsorption Isotherm ◽  
Fine Sand ◽  
Silty Clay ◽  
Field Soil ◽  
Clay Loam ◽  
Soil Columns ◽  
Silty Clay Loam ◽  
Time Period ◽  
Layer Chromatography ◽  
Comparable Time

In the field, surface applied cyanazine 2-[[4-chloro-6-(ethylamino)-s-triazin-2-yl] amino]-2-methylpropionitrile and diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] did not move below 5 cm in a Monona silty clay loam (Typic Hapludoll) which received 20 cm of water over a 54-day period. In hand-packed soil columns in the laboratory, surface-applied diuron and cyanazine penetrated to depths of 10 and 20 cm, respectively, when leached over a comparable time period and with amounts of water similar to that used in the field. Soil thin layer chromatography and adsorption isotherm studies showed that diuron was adsorbed more strongly than was cyanazine. In general, both compounds were degraded more rapidly at the higher temperatures when incubated at 5, 20, 35, and 50 C over a 20-week period. Degradation was slowest at 5 C in a Valentine loamy fine sand (Typic Ustipsamment). Diuron appeared to break down most readily at 35 C. Cyanazine was usually decomposed by the 10th week at 5 C and the 5th week at higher temperatures.

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