In-season pecan nut loss in Texas.
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| Format: | Thesis Book |
| Language: | English |
| Published: |
1982.
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| Subjects: | |
| Online Access: | Link to ProQuest Copy Link to OAKTrust copy ProQuest, Abstract |
| Abstract: | The pecan, Carya illinoensis (Wang.) K. Koch, was subjected to a life table analysis in order to assess the impact of pests and pathogens in various sites and treatment regimes in Texas. Nut clusters were initially tagged at the beginning of each growing season for the years 1977, 1978 and 1979. The number of nuts that dropped and the associated known causes of that nut drop were recorded for each year. These sites included trees grown under urban, wild, native and managed conditions that received anywhere from the full complement of recommended prophylactic treatments to no treatments at all. The highest percentage of recorded nut drop with unknown causes ranged from 36% to 83%. Estimated known nut loss from the pecan nut casebearer in areas that did not receive prophylactic treatments ranged from 2% to 45%, while estimated known nut loss from the pecan weevil in areas that did not receive prophylactic treatments ranged from less than 1% to 42%. Nut drop from pecan scab ranged from less than 1% to 20%. Several pathogen and arthropod interactions appear to be evident in this field study. Moderate to severe pecan scab caused by Fusicladium effusum Winter, was found to be more damaging by causing partially-filled nuts than by causing pops and nut drop (x('2) = 34; p (LESSTHEQ) .001). Hickory shuckworm, Laspeyresia caryana (Fitch), also appeared to cause partially-filled nuts as a result of shuck mining. The presence of hickory shuckworm larvae at harvest does not appear to be associated with pops or good nuts (x('2) = 114; (LESSTHEQ) .001). There also appeared to be a positive association between nuts attacked by both the hickory shuckworm and the pecan weevil, Curculio caryae (Horn) (x('2) = 2026; p (LESSTHEQ) .001). |
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| Item Description: | "Major subject: Entomology." Typescript (photocopy). Vita. |
| Physical Description: | xix, 174 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references (leaves 168-173). |