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Wood et al. (1987) report that M. caryella second and third instar nymphs excrete some fortyfold more honeydew than other pecan aphids (other life stage comparisons are three- to tenfold) and noted that some 95% of the 301 joules (J) of energy removed from pecan by one M. caryella aphid during its lifetime was due to honeydew excretion. M. cao'el/a energy consumption exceeds by 20% the largest consumption found in a review by Llewellyn (1987) for non-pecan aphids, and also has the lowest energy assimilation compared to other aphids. Honeydew is attractive to hundreds of species of insects (Klingauf 1987), including many predators and parasites. Tedders (1991) concluded pecan aphid honeydew "may be necessary for attracting and retaining large numbers of many beneficial species." Honeydew also improved the surrounding substrate for decomposers (Dixon 1985), enhancing the recycling of nutrients. These benefits must be balanced against the costs of M. cao'ella to pecan. Initial characterization of the costs of M. caryella requires accounting for energy lost to the aphid in relation to the overall photosynthate production capacity of the pecan. Wood et al. (1987) provide the former at 301.41 J for one M. caryella over a 19.3 d life span and calculate 11.42 J/d are removed by the average aphid in a population. Anderson (1991) reported pecan assimilates CO2 at a rate of 15.9 btmol/m2/s [Wood and Tedders (1986) report 11 g tool COJmZ/s]. Annual photosynthate productivity (PP)/ha, therefore, can be estimated by: Annual PP/ha = 2.65 bttool of glucose x 50,000 m2pecan foliage/ha x 6.25 x 106seconds/growing season x 0.5 x 0.65 [(corrected for photosynthetic efficiency due to shading (0.5) and respiration (0.65)]. Where CO 2 has been converted to glucose (1 glucose = 6 COz), pecan foliage/ha was averaged from Wood et al. (1987) who reported 35,900 mZ/ha, Cutler (1976) who reported 52,580 m2/ha and Lozano (1982) who found 62,800 m2/ha; a growing season was defined as 217 d with 8 hr of sunlight each day; photosynthetic efficiency was estimated at 50% and respiration costs at 35%. This results in a PP/ha of 2.69 x 10s mols of glucose annually or 185.98 x 106 kcal/ha (1 tool of glucose = 691 kcal). Pecan foliage routinely is exposed to BMA at a level of a 100 to 500 or so aphid days per compound leaf each season (Tedders 1978, Flores 1981, Li 1990, Liao and Harris 1984, Tedders and Wood 1985, Bumroongsook 1986, Mansour and Harris 1988). Pecan leaf density estimates vary from 2.2 to 3.6 x l0 bleaves/ha (Cutler 1976, Lozano 1982, Wood et al. 1987). Using an average of 3.0 x 106leaves/ha and 500 M. caryella aphid days/leaf/season results in an energy cost of 17.12 x 10'_J/ha annually (I 1.42 J/aphid day x 3.0 x 106leaves/ha x 500 aphid days). Since 1 J = 0.24 cal, this equates to 4.1 x 10 6 kcal as an average cost of BMA on each ha of pecan each season. Therefore, a 500 aphid day/leaf infestation of BMA each season would occur at a direct cost of about 2% (4.1 x 106 +185.98 x 1106)of the photosynthate production of the pecan. This cost would be spread across all physiological needs of the plant with only a portion appearing as yield loss. Secondary effects of factors like saprophagous sooty mold growth and additional reductions in photosynthetic efficiency are not discussed because previous studies (Tedders and Smith 1976, Wood and Tedders 1986) indicate BMA densities of 500 aphid days/leatTseason are too low to cause measurable reductions via these secondary effects in mature bearing trees. This view of BMA is more sanguine than that presented by Wood et al. (1987). Resistance to pesticides in the pecan pest complex makes the prospect of maintaining BMA below its natural equilibrium level fraught with additional pesticide costs and other secondary pest problems like mites, leafminers, and other aphids (Harris 1991). Wood et al. (1987) report an average of 10 aphicide sprays ($500/ha at $50/spray)required to achieve this, and Dutcher (1991) reports 50 kg/ha rates of aldicarb ($330/ha at $6.60/kg) needed to achieve the same end for aphid control from mid-July onward. Although these approaches may protect the = 2% of photosynthate production at risk from BMA, that loss represents 20 kg from an estimated average yield of 1,000 kg/ha if the entire BMA energy removed resulted in nut loss. Most insecticides currently used in pecans are highly toxic to most natural enemies of aphids (Mizell 1991) and in danger of being rendered ineffective due to aphid resistance to them (Harris 1991). We believe that the pecan aphid complex rarely poses a direct threat to pecan production unless disrupted by pesticides, especially in the early season and that the judicious use of pesticides for key pests can usually avoid these disruptions. When the problem is "viewed from this perspective, pest managers may wish to reevaluate the risks posed by BMA compared to the benefits provided by sustaining natural enemies and enhancing decomposition. Further study is needed to determine whether a natural role of BMA in the pecan ecosystem is to re-establish waning densities of natural enemies. 114
HARRIS, M.K. 1980. Arthropod-plant interactions related to agriculture, emphasizing host plant resistance, p. 23-51. In Biology and Breeding for Resistance. Dept. of Agric. Comm. TAES, Texas A&M University. MP-1451. HARRIS, M.K. 1983. Integrated pest management of pecans. Ann. Rev. Entomol. 28:291-318. HARRIS, M.K. and FREDERIKSEN, R.A. 1984. Concepts and methods regarding host plant resistance to avthropods and pathogens. Ann. Rev. Phytopath. 22: 247-272. HARRIS, M.K. 1988. Pecan domestication and pecan arthropods, p. 207-225. In The Entomology of Indigenous and Naturalized Systems in Agriculture. Westview Press Inc., Boulder, CO. HARRIS, M.K. 1991. Pecan arthropod management,, p. 6-15. In Wood, B.W. and Payne, J.A., eds. Pecan Husbandry: Challenges and Opportunities. First National Pecan Workshop Proceedings. ARS-96. U.S. Deptartment of Agriculture, Agriculture Research Service. HOWE, H.E, and WESTLEY, L.C. 1988. Ecological relationships of plants and animals. Oxford Univ. Press, Oxford. 273 p. KLINGAUF, EA. 1987. Feeding, adaption and excretion, p. 225-253. In Minks, K.A. and Harrewign, E, eds. Aphids: Their Biology, Natural Enemies, and Control. Elsevier, New York. LI, T. 1990. Population growth and factors affecting the seasonal abundance Monellia caryella (Fitch) and Monelliopsis pecanis Bissell in Central Texas. Ph.D. Dissertation, Texas A&M University, College Station, TX. 181 p. LIAO, H. and HARRIS, M.K. 1984. Population growth of the blackmargined aphid on pecan in the field. Agric. Ecol. Environ. 12: 353-361. LIAO, H., HARRIS, M.K., GILSTRAP, EE., DEAN, D.A., AGNEW, C.W., MICHELS, G.J., and MANSOUR, F. 1984. Natural enemies and other factors affecting seasonal abundance of the blackmargined aphid on pecan. Southw. Entomol. 9: 404-420. LIAO, H., HARRIS, M.K., GILSTRAP, EE., and MANSOUR, E 1985. Impact of natural enemies on the blackmargined pecan aphid, Monellia caryella (Homoptera: Aphidae). Environ. Entomol. 14: 122-126. LITTLE, E.L. 1971. Atlas of United States trees. Vol. 1. Conifers and important hardwoods. Misc. Publ. 1146. Washington, DC: U.S. Department of Agriculture, Forest Service. LLEWELLYN, M. 1987. Aphid energy budgets, p. 109-117. In Minks, A.K. and Harrewign, E, eds. Aphids: Their Biology, Natural Enemies, and Control Elsevier, New York. LOZANO, R. 1982. A three-dimensional characterization of a bearing pecan tree. M.S. Thesis, Horticulture, Texas A&M University, College Station, TX. 71 p. MAGGIO, R.C., HARRIS, M.K., INGLE, S.J., and DAVIS, M.R. 1991. A summary of the location, abundance, distribution, and condition of Carya on the Brazos and Colorado River systems of Texas. Dept. of Agric. Comm. TAES, Texas A&M Univ. MP-1703. MANSOUR, E and HARRIS, M.K. 1988. Biology and phenology of the blackmargined aphid, Monellia caryella (Fitch), a new pest of pecan in Israel. Southw. Entomol. 13: 19-29. 116
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DYNAMICS OF FOREST HERBIVORY: QUEST
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TABLE OF CONTENTS Seeking The Rules
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32. Companion planting of the nitro
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GRIMALSKY, ¥.I., Research Institut
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POUTTU, ANTTI, Finnish Forest Resea
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persist in mature leaves and affect
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THE SINK-SOURCE HYPOTHESIS: TYPE AN
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late season defoliation decreases t
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BLANCHE, C.A., LORIO, EL., Jr., SOM
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NIEMELA, R, TUOMI, J,, and LOJANDER
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induced reactions have been studied
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summer, but the other sawfly specie
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LARSSON, S., BJ(_RKMAN, C., and GRE
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STAND AND LANDSCAPE DIVERSITY AS A
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not related to resistance to the se
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In contrast to the situation in eas
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ROOT, R.B. 1973. Organization of a
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We tlhus neglect two potential sour
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c__ c__ 1T1 Ill a) a) 0 0 0 e 1 o e
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c_ >l.s S S S m N < DN DN < D c DN
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:hen k > 0 suggest that the cue or
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oth as protective weapons and as po
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DEFENSE THEORIES AND BIRCH RESISTAN
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P 45 A L 40 A T 35 A B 30 I L 25 I
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However, hares showed strong prefer
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DUGLE, J.A. 1966. A taxonomic study
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accommodate findings related to mic
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Table l.--Mean ±S.E. area eaten by
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Sulfhydryl-Disulfide Mechanisms In
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Iraa prior experimental analysis of
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FRAZIER, J.L. and HEITZ, J.R. 1975.
Page 68 and 69:
REICHARD, R 1993. From RNA to DNA,
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; trees, and between and within ind
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Encapsulated objects are data struc
Page 74 and 75: _re3.--The Lignum model can be cont
Page 76 and 77: SEVERE DEFOLIATION Tree Fine Root +
Page 78 and 79: RUMBAUGH, J., BLAHA, M., PREMERLANI
Page 80 and 81: oo0 a b ol ¢' _achiman_i ()® 1,eA
Page 82 and 83: 1000 Conspicuous Defo i at ion 100
Page 84 and 85: 2.oo 2.oo o t 4 t ¢._ e'- 1.80 1.8
Page 86 and 87: Qualitative Changes in [,eaves and
Page 88 and 89: t00 2 Yr 1 Yr o_ 80 Treatment Treat
Page 90 and 91: Table 2.--Body size of Q. purzctate
Page 92 and 93: 06 b AddedBSA < 04 _ 2rag -'=' i:3
Page 94 and 95: Severe Defol iat ion Site-A 1993 _
Page 96 and 97: KAMATA, N. and IGARASHI, M. 1995b.
Page 98 and 99: enclosure %r 20 post-diapausing sec
Page 100 and 101: 2,500 F 000 F NF NF b _7 a _;_ a _7
Page 102 and 103: 8O D 09 i 4,'.) F AS4L a Z___7 2o !
Page 104 and 105: 2,500 _ st2-st4 El st5 0 st6 [_ pup
Page 106 and 107: 96 SLANSKY, E, Jr. 1990. Insect nut
Page 108 and 109: later, we selected one more floweri
Page 110 and 111: Table 2.---Mean spruce budworm perf
Page 112 and 113: Table 3..--Mean spruce budworm perf
Page 114 and 115: FOLIVORE FEEDING ON MALE CONIFER FL
Page 116 and 117: Table 3.--Lymantria monacha prefere
Page 118 and 119: 500- 400- i 300 v ¢ m a 200- I00 L
Page 120 and 121: From the point of view of trees, th
Page 122 and 123: THE BLACKMARGINED APHID AS A KEYSTO
Page 126 and 127: MIZELL, R.E 1991. Pesticides and be
Page 128 and 129: METHODS Study Site The study took p
Page 130 and 131: the samples. Fertilization had subs
Page 132 and 133: Table 2.--Percent nutrient content
Page 134 and 135: Some tree responses to fertilizatio
Page 136 and 137: PHYTOCHEMICAL PROTECTION AND NATURA
Page 138 and 139: Indirect effects of abiotic factors
Page 140 and 141: HUNTER, M.D. and PRICE, P.W. 1992.
Page 142 and 143: A° ADDITIVE C. HYBRID SUSCEPTIBILI
Page 144 and 145: Galls, leaf miners, or leaf folds w
Page 146 and 147: Table 2.--Summary of the hypotheses
Page 148 and 149: the inheritance patterns of seconda
Page 150 and 151: FLOATE, K.D. and WHITHAM, T.G. 1993
Page 152 and 153: Elements of the Suitability/Defense
Page 154 and 155: Table l.--Comparing the mean number
Page 156 and 157: ACKNOWLEDGEMENTS The authors sincer
Page 158 and 159: SINGH, D.R 1986_ Breeding for resis
Page 160 and 161: The objectives of this presentation
Page 162 and 163: Table 1.--Average weevil attack on
Page 164 and 165: 1977, Kline and Mitchell 1979, Wood
Page 166 and 167: Further research is underway to cla
Page 168 and 169: A SUGI CLONE HIGHLY PALATABLE TO HA
Page 170 and 171: RESULTS Seasonal Stability of Palat
Page 172 and 173: -
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OGAWA, A., NAGATA, Y., and SUKENO,
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MATERIALS AND METHODS Field Work In
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Laboratory Procedures The week afte
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E 120 Nogent-sur-Vernisson Remnings
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Interdependence Between Reaction Zo
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alance hypothesis (Lorio 1986) cann
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SOLHEIM, H., LANGSTROM, B., and HEL
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In a second experiment, three 30-ye
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Considering biochemical pathways, i
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- = 120 N /'_" =40 1/ _ j Days 0 _
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BIGGS, A.R. 1985. Suberized boundar
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DIFFERENTIAL SUSCEPTIBILITY OF WHIT
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Table 2.--Mortality of white fir pr
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Results from the geographic range p
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esulting seedlings were then rooted
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-0.2 0 5 82. _j -0,4 e a a a D4 E I
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1960, Kalkstein 1976). Increased su
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RYAN, B.F., JOtNER, B.L., and RYAN,
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It is seldom feasible to control wa
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15 15 u. 10 |O O N tal 5 5 g ao o 4
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Only recently have we conducted stu
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esistance to beetle attack. Another
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LORIO, EL., Jr'. and HODGES, J.D. 1
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EFFECTS OF ROOT INHABITING INSECT-F
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OCCURRENCE OF ROOT AND STEM SUBCORT
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]Predisposition of Root-infected Tr
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chemistry associated with root colo
Page 228 and 229:
Implications to Natural Resource Ma
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KLEPZIG, K.D., RAFFA, K.F., and SMA
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RAFFA, K.F., PHILLIPS, T., and SALO
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METHODS The study was installed in
Page 236 and 237:
FURNISS, M.M., LIVINGSTON, R.L., an
Page 238 and 239:
METHODS In the spring and summer of
Page 240 and 241:
The importance of a compound as a r
Page 242 and 243:
WERNER, R.A. 1995. Toxicity and rep
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41 40 42 \ 4t 42 41 42 ",,,\ 42 40
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Table 1.--Summary data for the 26 p
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One weakness of using data from gen
Page 250 and 251:
Lower Peninsula (populations 14-26)
Page 252 and 253:
AUCLAIR, A.ND., WORREST, R.C., LACH
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KELLOMAKI, S., HANNINEN, H., and KO
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WARGO, RM. and HAACK, R.A. 1991. Un
Page 258 and 259:
investigation. Sampling was done on
Page 260 and 261:
Figure 2.--Changes in protein preci
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q) J 400 T J ! i i i i o control tr
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attacked trees than in control tree
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ACIDIC DEPOSITION, DROUGHT, AND INS
Page 268 and 269:
Table 1.--Impact of acidic fog upon
Page 270 and 271:
MENGEL, K., BREININGER, T., and LUT
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THE RESISTANCE OF SCOTCH PINE TO DE
Page 274 and 275:
EXPERIMENTAL METHODS Experiments we
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C w Q. 1,200 1,000 o 800 C_ --- 600
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0 .................................
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FONTAtNE, R.G. 1985. Forty years of
Page 282 and 283:
Host Defenses An important componen
Page 284 and 285:
Functional Heterogeneity of Forest
Page 286 and 287:
The Connectivity Index (CI). The CI
Page 288 and 289:
FUNCTIONAL HETEROGENEITYANALYSIS :
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The Modified Hazard Map. The next l
Page 292 and 293:
systems facilitate mapping of fores
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KOLASA, J. and ROLLO, C.D. 1991. In
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) i,i_i)i_)i_i_ U.S. Departme_]t of
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