Pheromone Trapping as an Indicator of Southern Corn Rootworm Damage in Peanut1

1992 ◽  
Vol 19 (1) ◽  
pp. 37-40 ◽  
Author(s):  
R. L. Brandenburg ◽  
J. D. Barbour ◽  
D. A. Herbert

Abstract Populations of adult male southern corn rootworms (SCR) were monitored, and percent pod damage evaluated, for 107 peanut fields in the peanut growing regions of northeastern North Carolina and southeastern Virginia from 1986 through 1990. percent pod damage was not consistently related to numbers of adult male SCR as determined by pheromone trap catches, for any of the five years, or for all five years combined. However, fields with trap catches less than or equal to 45 beetles per trap per week (17% of those sampled) appeared to be at low risk for SCR damage. When SCR numbers averaged less than 45 beetles per trap per week, percent pod damage averaged less than 3% and variation was low (standard deviation=2.1%), indicating that this number may be used as a low-end cutoff for SCR treatment. The critical dependence of SCR on adequate soil moisture for survival of eggs and early instar larvae may be a major factor contributing to the lack of correlation between numbers of adult SCR and damage to peanut pods under field conditions.

1997 ◽  
Vol 24 (2) ◽  
pp. 128-134 ◽  
Author(s):  
D. A. Herbert ◽  
W. J. Petka ◽  
R. L. Brandenburg

Abstract The southern corn rootworm, Diabrotica undecimpunctata howardi Barber, is a primary pest of peanut, Arachis hypogaea L., in Virginia and North Carolina and an occasional pest in South Carolina, Georgia, Alabama, and Texas. Currently, no alternatives involving integrated pest management exist for this pest, and control is based solely on preventive application of soil insecticides. Recent reductions in federal price support for peanut grown in the U.S. have provided incentives for growers to look for ways to reduce production costs. A risk index was developed that integrates factors that influence rootworm abundance and peanut pod damage to estimate levels of risk in individual peanut fields, and thus allows for more prescriptive and economical rootworm management. This index was evaluated using 44 field case studies in Virginia and North Carolina commercial peanut fields over the period 1989 to 1996. In each field case, predicted risk was compared to actual percent pod damage. Results showed that in 29 of 44 cases, the index accurately predicted general levels of risk to pod damage, and insecticide treatment decisions based on the index would have been correct in 32 of 44 cases. This report contains the individual index components, the justification for each, the indexing process, example index scenarios, and results of the process used in field case study evaluation.


1994 ◽  
Vol 21 (2) ◽  
pp. 88-91
Author(s):  
T. A. Coffelt ◽  
D. A. Herbert

Abstract Southern corn rootworm (SCRW) (Diabrotica undecimpunctata howardi Barber) is the most damaging soil insect to peanut (Arachis hypogaea L.) in the Virginia-North Carolina production area. New cultivars and advanced breeding lines have not been evaluated for resistance to SCRW. The objective of this 3-yr study was to evaluate three new cultivars (NC-V 11, VA-C 92R, and Agra Tech VC-1) and an advanced breeding line (VA 861101) for resistance to SCRW. NC 6 and NC 9 were used as resistant and susceptible checks, respectively. Pod damage, yield, market grade, and dollar value were obtained for each plot. Agra Tech VC-1, VA-C 92R, and VA 861101 had less total pod damage from SCRW than NC 9. VA 861101 produced significantly higher yields and value per ha than all cultivars on soil types conducive to SCRW damage. Insecticidetreated plots had significantly higher value per ha and lower total pod damage than untreated plots. Results from this study indicate that VA 861101 may be an acceptable replacement for NC 6. Agra Tech VC-1 is the most resistant of the newly released cultivars, but this is not reflected in higher yields.


1983 ◽  
Vol 115 (7) ◽  
pp. 717-722 ◽  
Author(s):  
Diane L. Mague ◽  
W. Harvey Reissig

AbstractPheromone trapping studies from 1979 to 1981 showed that there were two periods of San Jose scale, Quadraspidiotus perniciosus (Comstock), male flight activity annually in western New York apple orchards. Spring flight, which resulted from overwintering black caps, began at ca. 94–140 degree-days (base 10 °C from 1 March) and occurred during bloom in the apple varieties studied. First generation crawlers emerged at ca. 360 degree-days. Second generation crawlers emerged at ca. 890 degree-days and were active throughout September. Regression analyses showed a logistic relationship between crawler density and fruit infestation, and inverse linear relationships between pheromone trap catches and San Jose scale infestation levels within trees.


2004 ◽  
Vol 31 (1) ◽  
pp. 28-32 ◽  
Author(s):  
D. A. Herbert ◽  
S. Malone ◽  
R. L. Brandenburg ◽  
B. M. Royals

Abstract The southern corn rootworm, Diabrotica undecimpunctata howardi Barber, is an annual soil insect pest of peanut (Arachis hypogaea L.) in Virginia, North Carolina, Texas, and other peanut growing states. Larvae feed on developing pods causing direct yield loss and indirect damage by allowing entry of secondary pathogens. Because southern corn rootworm is a soil pest, scouting is difficult and producers make preventive treatments without knowledge of actual pest abundance. A predictive index for southern corn rootworm injury was evaluated using 392 field case studies conducted in Virginia and North Carolina from 1997 to 2001. Factors influencing the index score (soil texture, soil drainage class, planting date, cultivar resistance, and field history of rootworm damage), and point assignments for predicting low, moderate, and high-risk fields were analyzed. The goal of this project was to determine which combination of factors provided the highest percentage of correct risk predictions. The best index combination used all five factors to determine the total point score, with 70 or more points indicating a high-risk field, 55 to 65 points a moderate-risk field, and less than or equal to 50 points a low-risk field. Growers who use the index eliminate a preventive insecticide treatment in low-risk and some moderate-risk fields. The index correctly predicted the level of pod damage in 45% (177 of 392) of the field case studies. Insecticide was correctly recommended in 46 fields. Thirty-three percent (131 of 392) of the fields were correctly identified as not needing treatment. There were 209 cases where there was an overestimation of pod damage with predictions of either a high or moderate level when only a low level occurred. In these cases, an insecticide treatment would have been recommended and an average of 6.1 and 2.6% pod damage, respectively, would have been prevented. Conversely, there were very few fields that should have been treated but were not treated (6 of 392). Overall, use of the index would have protected fields from pod damage and potential loss 98.5% of the time.


2011 ◽  
Vol 64 ◽  
pp. 291-291
Author(s):  
P.W. Shaw ◽  
D.R. Wallis

Potential applications for synthetic sex pheromones for two troublesome mealybug species found in New Zealand Pseudococcus calceolariae (citrophilus) and P longispinus (longtailed) are ongoing The aim of this pilot study was to compare the results of seasonlong pheromone trapping for both species with crop infestation assessments at harvest A total of four traps of each species was monitored in three commercial Nelson orchard blocks between September 2010 and April 2011 Trapping indicated a sharp peak in male citrophilus mealybug flight activity in mid February with a gradual decline thereafter Longtailed mealybug flight activity increased during March and peaked in late April when trapping ceased Higher numbers of citrophilus mealybug males (36764) were trapped than longtailed mealybug (693) At harvest mealybugs were identified on 357 infested fruit and 295 infested leaves to determine mealybug species composition and relative abundance The dominant species was longtailed mealybug identified on 92 of infested fruit Citrophilus and obscure mealybugs (P viburni) were identified on 3 and 5 of infested fruit respectively From the leaf sample 410 longtailed 4 obscure and no citrophilus mealybugs were identified These results indicate pheromone trap catches do not reflect species abundance in the crop Possible reasons for these results are discussed


1992 ◽  
Vol 19 (2) ◽  
pp. 98-100 ◽  
Author(s):  
D. A. Herbert ◽  
R. L. Brandenburg ◽  
E. R. Day

Abstract Sixty peanut (Arachis hypogaea L.) fields were surveyed for wireworms (Coleoptera: Elateridae) in the Virginia-North Carolina peanut area in 1989 and 1990. A series of baited container soil traps was placed in each field once in early June and again in early August for a total of 605 trap-weeks (trap per field per week = 1 trap-week)). Trap capture was similarly low in both states and in both years with a total of 59 wireworm specimens collected: an average of one wireworm per field per year. Species composition was similarly diverse with Conoderus vespertinus F. comprising 58 percent, C. lividus De Geer 20 percent, Glyphonx sp. 8 percent, Melanotus communis Gyllenhal 7 percent, C. sp. 5 percent, and C. bellus Say 2 percent. Even though wireworm captures were low, moderate to high levels of pod damage were observed. The large number of southern corn rootworm (Diabrotica undecimpunctata howardi Barber) adults detected on nearby pheromone baited sticky traps indicated that most pod damage was not by wireworm but by southern corn rootworm. Implications are that although several wireworm species can be found in association with peanut, they appear to play only a minor role in peanut pod damage in the survey area.


2008 ◽  
Vol 35 (1) ◽  
pp. 32-37 ◽  
Author(s):  
David L. Jordan ◽  
Rick L. Brandenburg ◽  
P. Dewayne Johnson ◽  
Brian M. Royals ◽  
Brenda Watson

Abstract Experiments were conducted from 2004 through 2006 in North Carolina to determine peanut injury, pod scarring, pod yield, and percentages of extra large kernels (%ELK), fancy pods (%FP), and total sound mature kernels (%TSMK) following chlorpyrifos applied as a granular at pegging or as emulsifiable concentrate applied preplant incorporated (PPI) in mixture with pendimethalin. In one experiment, preemergence (PRE) herbicides consisted of S-metalochlor, S-metalochlor plus diclosulam, and S-metalochlor plus flumioxazin following chlorpyrifos. In a separate experiment, the postemergence (POST) herbicides acifluorfen, acifluorfen plus bentazon, imazapic, and paraquat plus bentazon were applied when peanut diameter was 10 to 15 cm. Chlorpyrifos did not interact with diclosulam or flumioxazin applied PRE or with the POST herbicides acifluorfen, acifluorfen plus bentazon, imazapic, or paraquat plus bentazon with respect to visual injury and pod yield. Applying chlorpyrifos at pegging was more effective than PPI applications in reducing pod scarification caused by southern corn rootworm (Diabrotica undecimpunctata Howardi) feeding. Although PRE and POST herbicides injured peanut in a manner consistent with standard application of these herbicides, pod yield, %ELK and %TSMK were not affected by early season injury. However, pod yield was lower in the experiment with POST herbicides when chlorpyrifos was applied PPI compared with granular application at pegging. No differences in pod yield, %ELK, %FP, and %TSMK were noted when comparing PPI and pegging applications of chlorpyrifos in the PRE herbicide experiment.


1976 ◽  
Vol 66 (2) ◽  
pp. 279-300 ◽  
Author(s):  
R. J. Marks

AbstractThe synthetic sex pheromone (dicastalure) of the red bollworm of cotton, Diparopsis castanea Hmps., in Central and Southern Africa, and an inhibitor of male sexual attraction (trans-9-dodecenyl acetate,=IIA), were used in an enclosed 0·2 ha cotton field-cage to reduce successful female matings. Over one month dicastalure at 21·0 and 42·3 g/ha produced average reductions in mating of 47·9% and 72·5% respectively and 37·9 g IIA/ha produced an overall reduction in mating of 71·5%, or 79·5% in released moth populations, over the same period. The proportion of virgin females present in disruption situations was significantly greater than in untreated populations and was density-independent for moth populations of up to 2 200/ha. The proportion of fertile eggs in disruption situations was correspondingly reduced to 30·2% from an average of 67·9% in control cycles. Reduction in sex pheromone trap catches is an unsatisfactory indicator of the extent to which males are prevented from inseminating females and considerably over-estimates the true degree of disruption. This is the first time that a naturally occurring inhibitor has been used successfully to disrupt mating in a field population of insects and it indicates the potential of the method for the control of high density pest populations in cotton. However, use of polyethylene dispensing mechanisms similar to those used in the field-cage disruption experiments would be unsuitable as a practical method of dispensing behaviour modifying chemicals and it is suggested that, for suitably controlled release of such chemicals, currently available microencapsulation technology offers the best prospects.


1985 ◽  
Vol 117 (2) ◽  
pp. 139-142 ◽  
Author(s):  
Olga Piedrahita ◽  
C. R. Ellis ◽  
O. B. Allen

AbstractThe relative density of corn-rootworm larvae was estimated in two field plots with 4 different plant spacings and with up to 4 plants clumped per location. In both fields the relationship between plant spacing and the number of corn rootworms per sample was similar with the maximum number of larvae occurring when plants were 46 or 50 cm apart. The number of plants clumped per location affected the numbers of corn rootworm in only one field. The relationship between clumping of plants and number of corn rootworms was curvilinear in this field with the most corn rootworms occurring at 3 plants per location.


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