[Edited_by_A._Ciancio,_C.N.R.,_Bari,_Italy_and_K.(Bookos.org)

IPM IN PECAN PRODUCTION
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hemipterans. Pyrethroid insecticides are also used but have a shorter residual activity
and lower toxicity against the pecan weevil. Broad spectrum insecticides are not
ideal and sprays often destroy beneficial insects leading to resurgence of secondary
foliage-feeding pests. Pecan growers with resurgence problems have to apply
additional costly and specific aphidicides, systemic insecticides and/or miticides to
keep the foliage on the trees.
Systemic insecticides or foliar sprays of insecticides are the most effective
controls for outbreaks of foliage feeding insects. Phosmet and chlorpyrifos are used
effectively for control of late season outbreaks of the black pecan aphid. These two
organophosphate insecticides may become obsolete through reassessment.
Imidacloprid sprays and biological control with multicolored Asian ladybeetle are
effective against the pecan aphids. Efficacy varies between the three different
species and selective control of two aphid species and not the third species opens the
feeding niche the third leading to outbreaks. The control of all three species of pecan
aphids can leave the foliage open to attack by phytophagous mites and typically
leads to an outbreak of pecan leaf scorch mite (Dutcher et al., 2006). Alternative
controls for control of nut-feeding pests that do not destroy beneficial insects
associated with foliage-feeding pests are possible with the use of selective
insecticides.
Growers also adopt insect pest management to reduce the cost of production for
pecans. Pecan growers typically minimize the number of spray applications and rely
on natural control by predators, parasites and pathogens for many insect pests. One of
the most effective biologically-based control techniques for pecan growers is selective
insecticides coupled with effective monitoring techniques. to control pecan nut
casebearer (Knutson & Ree, 2000) and hickory shuckworm. Replacement of broad
spectrum insecticides with biorational insecticides has reduced the incidence of
secondary pest resurgence after treatments for these pests. Initially, insect growth
regulators were evaluated for insect control against pecan weevil and lepidopterans
(Payne & Dutcher, 1985; Tedders, 1977). Efficacy was much lower than the broadspectrum
insecticides and registration was not pursued. Broad-spectrum insecticides
became the main control measures for preventing pest damage. Recently, newer and
more effective insect growth regulator insecticides, such as, diflubenzuron and
tebufenozide, have gained acceptance among growers for control of lepidopteran
pests. Broad spectrum insecticides are currently the only effective controls for pecan
weevil, kernel-feeding hemipterans and black pecan aphid.
Pecan insects have sufficient reproductive capacities to overcome the mortality
caused by control methods and growers are continually battling recurring pest
problems each season. The bionomics information for the reproductive capacity and
generation time of pecan weevil (Ree, Knutson, & Harris, 2005), pecan nut
casebearer (Mulder & Grantham, 2002), yellow pecan aphid, blackmargined aphid,
black pecan aphid (Tedders, 1978; Kaakeh & Dutcher, 1992), and pecan leaf scorch
mite (Hall, 2001) (Table 2) indicates that only 0.1–70% of the populations need to
survive from one season to the next to sustain the pest populations.
Pecan weevil survival of 2.6% per generation is needed to sustain the current
population level. Since there is a generation every 2–3 years, an annual mortality of
30.1% per season (for weevils with a 3-year generation time) or 83.4% per season