Climatic Data-Based Analysis of Boll Weevil (Coleoptera: Curculionidae) Overwintering Survival and Spring Emergence

1996 ◽  
Vol 25 (5) ◽  
pp. 882-894 ◽  
Author(s):  
M. N. Parajulee ◽  
L. T. Wilson ◽  
D. R. Rummel ◽  
S. C. Carroll ◽  
P. J. Trichilo
Keyword(s):  
Boll Weevil ◽  
Climatic Data ◽  
Overwintering Survival ◽  
Spring Emergence

Simulation of Boll Weevil (Coleoptera: Curculionidae) Spring Emergence and Overwintering Survival in the Texas Rolling Plains

1990 ◽  
Vol 19 (1) ◽  
pp. 91-98 ◽  
Author(s):  
Nicholas D. Stone ◽  
Don R. Rummel ◽  
Stan Carroll ◽  
Merry E. Makela ◽  
Raymond E. Frisbie
Keyword(s):  
Boll Weevil ◽  
Rolling Plains ◽  
Overwintering Survival ◽  
Spring Emergence

Temperature Thresholds for Spring Emergence and Flight of the Boll Weevil 12

1979 ◽  
Vol 8 (6) ◽  
pp. 1118-1122 ◽  
Author(s):  
Davy Jones ◽  
Winfield L. Sterling
Keyword(s):  
Boll Weevil ◽  
Temperature Thresholds ◽  
Spring Emergence

Supercooling in the Adult Boll Weevil (Coleoptera: Curculionidae) Relative to Physiological Condition and Diet

2007 ◽  
Vol 42 (3) ◽  
pp. 320-328 ◽  
Author(s):  
Charles P.-C. Suh ◽  
Dale W. Spurgeon
Keyword(s):  
Boll Weevil ◽  
Physiological Status ◽  
Anthonomus Grandis ◽  
Cotton Production ◽  
Flower Buds ◽  
Freezing Temperatures ◽  
Overwintering Mortality ◽  
Survival Studies ◽  
Overwintering Survival ◽  
Pollen Sacs

Severe winter temperatures are known to reduce overwintering survival of the boll weevil (Anthonomus grandis Boheman), but the mechanisms responsible for overwintering mortality are poorly understood. We examined the effects of adult physiological status (reproductive, diapause, intermediate diapause), diet (flower buds or fruit of cotton, Gossypium hirsutum L.) and time since feeding (0 or 2 d) on freezing points of weevils. Differences in supercooling points among weevil physiological states were not detected. However, adults fed cotton fruit (bolls) supercooled to lower temperatures (mean ± SE; −17.4 ± 0.23°C) than those initially fed flower buds (squares) followed by bolls (−15.8 ± 0.40°C). Weevils fed squares exhibited the highest mean supercooling point (−14.4 ± 0.35°C). Additional study confirmed the effects of diet on supercooling when weevils were exposed to freezing temperatures immediately after feeding (bolls, −12.5 ± 0.45°C; squares, −10.2 ± 0.45°C). However, supercooling points were lowered but similar for both diets when exposure to freezing temperatures occurred 2 days after feeding (bolls, −17.1 ± 0.45°C; squares, −17.2 ± 0.46°C). Also, tissues excised from bolls froze at lower temperatures (−10.7 ± 0.41 °C) than pollen sacs excised from squares (−8.2 ± 0.41°C). We found that supercooling ability did not indicate weevil physiological status. Furthermore, the observed supercooling points suggest that acute freezing is an unlikely mortality mechanism in the more southerly U.S. cotton production regions. Regardless, both diet type and the time since feeding are important factors that should be considered in supercooling or survival studies involving temperatures low enough to freeze weevils.

scholarly journals Enhanced Overwintering Survival of Stevia by QoI Fungicides Used for Management of Sclerotium rolfsii

Plant Disease ◽  
2017 ◽  
Vol 101 (8) ◽  
pp. 1417-1421 ◽  
Author(s):  
A. M. Koehler ◽  
H. D. Shew
Keyword(s):  
Sclerotium Rolfsii ◽  
Stevia Rebaudiana ◽  
Qoi Fungicides ◽  
Quinone Outside Inhibitor ◽  
Efficacy Trials ◽  
Progress Curve ◽  
Stem Necrosis ◽  
Overwintering Survival ◽  
Spring Emergence

Stevia (Stevia rebaudiana) is a herbaceous perennial under evaluation as a new crop in the southeastern United States. Stem rot caused by Sclerotium rolfsii is common in stevia plantings in North Carolina, with symptoms including wilting, root and stem necrosis, and plant death. Fungicide efficacy trials for management of S. rolfsii were conducted over 2 years. Fungicides evaluated included azoxystrobin, flutolanil, and tebuconazole applied at three timings. Azoxystrobin applied to transplants 1 week prior to planting had the lowest area under the disease progress curve values across all trials. Fungicide plots were also used to evaluate overwintering of stevia. End-of-season stand counts were compared with spring emergence counts to quantify overwintering survival. In spring 2015, plots treated with azoxystrobin in 2014 had greater overwintering survival (78%) than other fungicide treatments (38%) and the control (38%). Similar results were obtained at two locations in spring 2016 in plots treated with azoxystrobin or pyraclostrobin in 2015. Successful overwintering of stevia directly impacts the profitability of second- and third-year harvests and enhances the likelihood of long-term establishment of stevia as a viable crop. Future studies will be directed at elucidating the mechanism of the enhanced overwintering survival of plants treated with quinone outside inhibitor fungicides.

A Note on Patterns of Wear Within the Tread Area

1979 ◽  
Vol 7 (1) ◽  
pp. 3-13
Author(s):  
F. C. Brenner ◽  
A. Kondo
Keyword(s):  
Content Analysis ◽  
Groove Depth ◽  
Climatic Data ◽  
Periodic Behavior ◽  
Harmonic Content ◽  
Straight Line ◽  
Data Points

Abstract Tread wear data are frequently fitted by a straight line having average groove depth as the ordinate and mileage as the abscissa. The authors have observed that the data points are not randomly scattered about the line but exist in runs of six or seven points above the line followed by the same number below the line. Attempts to correlate these cyclic deviations with climatic data failed. Harmonic content analysis of the data for each individual groove showed strong periodic behavior. Groove 1, a shoulder groove, had two important frequencies at 40 960 and 20 480 km (25 600 and 12 800 miles); Grooves 2 and 3, the inside grooves, had important frequencies at 10 240, 13 760, and 20 480 km (6400, 8600, and 12 800 miles), with Groove 4 being similar. A hypothesis is offered as a possible explanation for the phenomenon.

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