Winter starch reserves of white oak as a predictor of attack by the twolined chestnut borer,Agrilus bilineatus (Weber) (Coleoptera: Buprestidae)

Summary The twolined chestnut borer, Agrilus bilineatus (Weber) (Coleoptera: Buprestidae), attacks oaks (Quercus spp.) and is associated with extensive mortality of trees in the eastern deciduous forests of North America. We tested the hypothesis that winter starch reserves of oak roots are an indicator of tree vigor and that only trees low in stored starch would be attacked by A. bilineatus. We measured the levels of stored starch in the roots of 200 non-infested healthy white oaks during the dormant season and determined their correlation with A. bilineatus attacks the following spring. There was a significant increase in A. bilineatus captures on sticky traps with a decrease in winter starch reserves. Trees low in stored starch that were also stressed by phloem-girdling attracted 3.7 times as many beetles as did non-girdled trees that were low in starch. However, non-girdled trees that had low winter starch reserves were also attacked. Only oaks that had had extremely low winter root starch reserves (<5mg/g dry weight of root sapwood tissue) were heavily attacked by A. bilineatus and subsequently died. One third of non-girdled low starch trees and 67% of phloem-girdled low starch trees died, whereas none of the trees with root starch >5 mg/g dry wt died. These results indicate that winter starch reserves are a good predictor of A. bilineatus attack.The investigation reported in this paper (No. 87-7-8-118) is in connection with a project of the Kentucky Agricultural Experiment Station and is published with the approval of the Director     

The role of host tree condition in attack of white oaks by the twolined chestnut borer,Agrilus bilineatus (Weber) (Coleoptera: Buprestidae)

Summary The twolined chestnut borer, Agrilus bilineatus (Weber) (Coleoptera: Buprestidae), attacks stressed oaks (Quercus spp.) and is associated with extensive mortality of trees in the eastern deciduous forests of North America. We examined host location by the insect and subsequent host mortality in experimentally stressed trees. A. bilineatus adults were able to rapidly and specifically locate stressed oak trees. Up to 160 beetles per week were captured on sticky band traps on the trunks of stressed trees, while beetles rarely landed on unstressed control trees. This suggests that adult borers have an acute perception of host tree quality, and that this perception is from a distance. One mechanism of host location may be detection of volatile compounds produced by stressed trees.The condition of the host tree appears to regulate both beetle attraction and successful colonization. Mortally wounded (xylem-girdled) trees attracted beetles only until the cambium died. Xylem-girdled trees were attacked early in the beetle flight season, but larvae did not survive to emerge as adults from these trees. In contrast, phloemgirdled trees continued to attract beetles throughout the flight period. Phloem-girdled trees which were heavily attacked by A. bilineatus died late in the season in which they were attacked. Lightly attacked trees survived until the following growing season, and were then heavily attacked and killed. In one stand, phloem-girdled trees were not attacked, healed over the girdling wounds and were still alive three years after girdling. These results indicate that oak trees are only attractive to A. bilineatus within a narrow range of physiological conditions following stress but prior to mortality. A. bilineatus appears to be a proximate agent of mortality in stressed oaks in eastern North America.This paper (85-7-8-216) resulted from a project of the Kentucky Agricultural Experiment Station and is published with the approval of the Director     

Changes in the localization and levels of starch and lipids in cambium and phloem during cambial reactivation by artificial heating of main stems of Cryptomeria japonica trees

Background and Aims

Cambial reactivation in trees occurs from late winter to early spring when photosynthesis is minimal or almost non-existent. Reserve materials might be important for wood formation in trees. The localization and approximate levels of starch and lipids (as droplets) and number of starch granules in cambium and phloem were examined from cambial dormancy to the start of xylem differentiation in locally heated stems of Cryptomeria japonica trees in winter.

Methods

Electric heating tape was wrapped on one side of the stem of Cryptomeria japonica trees at breast height in winter. The localization and approximate levels of starch and lipids (as droplets) and number of starch granules were determined by image analysis of optical digital images obtained by confocal laser scanning microscopy.

Key Results

Localized heating induced earlier cambial reactivation and xylem differentiation in stems of Cryptomeria japonica, as compared with non-heated stems. There were clear changes in the respective localizations and levels of starch and lipids (as droplets) determined in terms of relative areas on images, from cambial dormancy to the start of xylem differentiation in heated stems. In heated stems, the levels and number of starch granules fell from cambial reactivation to the start of xylem differentiation. There was a significant decrease in the relative area occupied by lipid droplets in the cambium from cambial reactivation to the start of xylem differentiation in heated stems.

Conclusions

The results showed clearly that the levels and number of storage starch granules in cambium and phloem cells and levels of lipids (as droplets) in the cambium decreased from cambial reactivation to the start of xylem differentiation in heated stems during the winter. The observations suggest that starch and lipid droplets might be needed as sources of energy for the initiation of cambial cell division and the differentiation of xylem in Cryptomeria japonica.     

Seasonal development of secondary xylem and phloem in <Emphasis Type="Italic">Schizolobium parahyba</Emphasis> (Vell.) Blake (Leguminosae: Caesalpinioideae)

The cambial activity and periodicity of secondary xylem and phloem formation have been less studied in tropical tree species than in temperate ones. This paper describes the relationship between seasonal cambial activity, xylem and phloem development, and phenology in Schizolobium parahyba, a fast growing semideciduous seasonal forest tree from southeastern Brazil. From 2002 to 2003, wood samples were collected periodically and phenology and climate were recorded monthly in the same period. S. parahyba forms annual growth increments in wood, delimited by narrow initial parenchyma bands. The reduction of the cambial activity to a minimum correlates to the dry season and leaf fall. The higher cambial activity correlates to the wet season and the presence of mature leaves. In phloem, a larger conductive region was observed in the wet season, when the trees were in full foliage. The secondary phloem did not exhibit any incremental zone marker; however, we found that the axial parenchyma tends to form irregular bands.     

Dynamics of twolined chestnut borer Agrilus bilineatus as influenced by defoliation and selection thinning

1 The twolined chestnut borer, Agrilus bilineatus (Coleoptera: Buprestidae), is a major mortality agent of stressed oak trees. However, patterns of abundance and population change are not well understood. 2 We studied the spatial and temporal variation in abundance of twolined chestnut borer adults during a gypsy moth, Lymantria dispar (Lepidoptera: Lymnatriidae), outbreak and examined the influence of both defoliation and thinning on twolined chestnut borer abundance. 3 In stands that were defoliated by gypsy moth, extensive defoliation occurred in one year, and major overstory tree mortality followed in the next. Most mortality occurred in the year preceding the peak year of twolined chestnut borer abundance and abundance of twolined chestnut borer was positively associated with defoliation and mortality in the previous year. 4 Twolined chestnut borers were more frequently associated with poor or fair crown condition trees than trees with good crown condition and were more abundant on members of the red oak group than the white oak group.     

Seasonal changes in the utilization and turnover of assimilation products in 8-year-old Scots pine (Pinus sylvestris L.) trees

Summary The present study aimed at a physiological understanding of the seasonal changes of the carbohydrate patterns and levels in the various tissues of 8-year-old Scots pine (Pinus sylvestris L.) trees growing under ambient climatic conditions in the botanical garden at Bayreuth. The photosynthates of selected twig sections were labelled by ¹⁴CO₂ fixation and after chase periods of 1 h up to 8 months, the distribution of radiocarbon in the whole trees was determined and the labelling of identified carbohydrates was compared with the levels of these compounds in the individual tissues. Bud break and sprouting in spring is exclusively supplied by the recent photosynthates of the previous year's needles. During summer assimilates of the old needles were utilized for secondary growth of the axial system while growth of the recent-year's shoots was supported by their own photosynthesis. In autumn, soluble carbohydrates were produced instead of starch, a major part of which in addition to recent photosynthates was utilized for root growth during the cold season. Another part of the autumnal storage material was incorporated into the cell walls of the latest xylem and phloem elements still in winter. A pronounced starch-oligosaccharide interconversion upon frost hardening, and its reversal in spring as has been described for deciduous trees, could not be observed. This was due to maintenance of photosynthetic capability even in the cold season and the replacement of consumed storage material especially in late winter and early spring by new photosynthates.     

Stem anatomy of Dolichos lablab Linn (Fabaceae): Origin of cambium and reverse orientation of vascular bundles

Secondary growth in the stem of Dolichos lablab is achieved by the formation of eccentric successive rings of vascular bundles. The stem is composed of parenchymatous ground tissue and xylem and phloem confined to portions of small cambial segments. However, development of new cambial segments can be observed from the obliterating ray parenchyma, the outermost phloem parenchyma and the secondary cortical parenchyma. Initially cambium develops as small segments, which latter become joined to form a complete cylinder of vascular cambium. Each cambial ring is functionally divided into two distinct regions. The one segment of cambium produces thick-walled lignified xylem derivatives in centripetal direction and phloem elements centrifugally. The other segment produces only thin-walled parenchyma on both xylem and phloem side. In mature stems, some of the axial parenchyma embedded deep inside the xylem acquires meristematic activity and leads to the formation of thick-walled xylem derivatives centrifugally and phloem elements centripetally. The secondary xylem comprises vessel elements, tracheids, fibres and axial parenchyma. Rays are uni-multiseriate in the region of cambium that produces xylem and phloem derivatives, while in some of the regions of cambium large multiseriate, compound, aggregate and polycentric rays can be noticed.     

Duration of diapause in the stem borers, Busseola fusca and Chilo partellus

The duration of diapause in the stem borers Busseola fusca (Fuller) and Chilo partellus (Swinhoe) was studied in South Africa by collecting diapausing larvae from the field throughout winter (April–August). B. fusca larvae emerged as moth around the middle of October regardless of the date of collection and the length of time they were kept in the laboratory under constant 21 °C. C. partellus larvae collected in April–June emerged in November, those collected in July emerged in October, and those collected in August emerged in September. Regardless of the collection date C. partellus started to emerge from diapause earlier and moth emergence lasted up to twice as long as in B. fusca. Under laboratory conditions at 60% RH both borer larvae lost about 50% of their body mass during diapause. When provided with water B. fusca larvae lost about 30% of their body mass and adults emerged 20 days earlier than when kept dry. C. partellus, on the other hand, lost only 13% of their body weight and emerged 34 days earlier. The differences between the two species are discussed in light of different types of diapause; i.e., obligatory diapause in B. fusca and facultative diapause in C. partellus.     

Field evaluation ofAllorhogas pyralophagus [Hym.: Braconidae], imported into texas for biological control of the stalkborerEoreuma loftini [Lep.: Pyralidae] in sugar cane

The external, gregarious, braconid parasite,Allorhogas pyralophagus Marsh was mass released into field cages enclosing sugar cane infested with the pyralid,Eoreuma loftini (Dyar) to examine factors affecting parasitism rates and to assess the parasite's potential contribution to borer larval mortality. Three field experiments were conducted in July, September, and December, 1984. Total parasitism was 25.2% for the study and was the single most important source of borer mortality. Borers were equally susceptible to attack in leaf sheaths, whorls, and stalks in general, but larvae tunneling deep within stalks were parasitized less. An interaction between tunneling behavior of the borer and attack strategy of the parasite was important for parasite success.A. pyralophagus is probably unable to effect complete control ofE. loftini in sugar cane becauseA. pyralophagus is physically unable to parasitize borers deep in the stalks. However, the parasite may be useful as part of an intergrated pest management program, acting in concert with other parasite species, or attacking the borer in small-stemed grasses that serve as alternate host plants.      

Moisture content and nutrition as selection forces for emerald ash borer larval feeding behaviour

1. The exotic phloem‐feeding emerald ash borer (EAB), Agrilus planipennis, has killed tens of millions of North American ash trees (Fraxinus) since its first detection in the U.S.A. in 2002. Ash trees are killed by larval feeding in the cambial region, which disrupts translocation of photosynthates and nutrients. 2. We observed that EAB larvae feed predominantly downwards in naturally grown green ash trees, a behaviour confirmed in greenhouse‐grown black ash seedlings. Furthermore, biomass of larvae feeding downwards was greater than that for larvae feeding upwards. 3. We sought to determine the relative importance of four selection forces (i.e. gravity, moisture content, plant defence, and nutrition) in driving this downward feeding behaviour in this study. The gravity and plant defence (i.e. polyphenols) hypotheses were ruled out because even when seedlings were grown upside down, more EAB larvae moved upwards (towards the root area), and phloem tissue below the feeding site contained higher concentrations of defensive compounds than that above the feeding site. 4. The moisture content hypothesis was supported as phloem moisture above the feeding site decreased to levels reducing survivorship and biomass but was unaffected below. The nutrition hypothesis was also supported as the levels of 11 amino acids (mostly essential amino acids) below the feeding site were greater than those above. Furthermore, growth of larvae reared on an artificial diet deficient in protein and amino acids was worse than larvae reared in diet with complete ingredient or diet deficient in either protein or amino acids. 5. We conclude that moisture content and nutrients are two selective forces for the downward feeding behaviour of EAB larvae.     

Responses of the African Armyworm and three species of borers to carbohydrates and phenolic substances: an electro- and behavioural physiological study

Electrophysiological recordings were made from the maxillary sensilla styloconica of fifth instars of the African Armyworm, Spodoptera exempta (Wlk.) (Lep.: Noctuidae), and the borers (Lep.: Pyralidae) Eldana saccharina Wlk. and Maruca testulalis (Geyer), and fifth and sixth instars of the borer Chilo partellus (Swinhoe). Stimuli were different concentrations of 13 carbohydrates and 11 phenolic substances. It appeared that a sucrose sensitive cell is present in the lateral styloconic sensilla of Spodoptera, Maruca and Chilo, and in both the lateral and medial sensilla of Eldana. The sucrose cell of fifth-instar Chilo is more sensitive than that of sixth instars. The additional responses of the medial cells to the phagostimulant sucrose are supposed to have contributed to the widespread infestation of sugarcane by Eldana. The medial sensilla of the Armyworm contain a cell type responding to both meso-inositol and D-ribose. Chilo appeared to be the only one of the three borer species able to perceive phenolic substances. It has a cell responsive to chlorogenic acid in its medial sensilla, which is a bit more sensitive in fifth- than in sixth-instar larvae. The presence of this cell may account for the positive correlation between total phenols content and resistance of sorghum cultivars to this borer. Spodoptera can perceive four phenolic acids. Its lateral sensilla contain a cell responsive to chlorogenic acid and its medial sensilla a cell responsive to 4-hydroxybenzoic acid, gallic acid as well as vanillic acid. Feeding experiments showed that the latter substances inhibit feeding in the Armyworm.So far, in the borers adequate stimuli could be determined for only tow or three of the four taste cells present in each sensillum styloconicum. This indicates that we are still unaware of chemicals that may be important to these caterpillars. On the other hand, for the sensilla styloconica of Spodoptera, electrophysiology suggests the presence of five or six taste cell types, whereas only four taste cells are known from morphological studies.     

Wood‐boring insect abundance in fire‐injured ponderosa pine

• 1 Wood‐boring larvae in the families Cerambycidae and Buprestidae are often found in high densities in burned trees after wildland fires. They play an important role in tree decomposition, often reducing the value of salvageable timber, and represent an important avian food source.
• 2 Three forest areas that experienced wildfires 1–3 years previously were surveyed during the summer of 2004. Ponderosa pine trees with green, scorched and consumed needles were examined for wood borer occurrence. Within each of the three needle damage categories, the mean wood borer incidence was similar between different age fires. Trees with scorched or consumed needles had significantly more wood borers than trees with green needles.
• 3 Larvae collected from under tree bark were identified to family; when possible, cerambycids were identified further to Acanthocinus spp., Monochamus sp., Rhagium inquisitor (L.) and Stictoleptura canadensis (LeConte), and buprestids were identified to Chalcophora spp. and Chrysobothris sp.
• 4 Classification tree models showed that the estimated probability of tree infestation by wood borers varied among needle damage categories. For trees with green needles, tree injury variables of high bole char height and phloem discolouration were important predictive variables. In trees where needles were consumed, tree size variables of diameter at breast height and tree height were important predictive variables.
• 5 More than half the dead trees examined were infested with wood borers, indicating that infestation of fire‐killed ponderosa pine may represent an important food source for species such as woodpeckers and a potential problem for the utilization of infested trees.

     

Delayed inducible resistance against a leaf-chewing insect in four deciduous tree species

Summary Both mechanical damage to mountain birch foliage and rearing of moth larvae on the trees reduced the growth of Epirrita autumnata larvae reared on these trees in the following year. The effects of physical damage and some other cues from insects were additive. On bird cherry the performance of Epirrita larvae was equal on untreated trees and on trees artificially defoliated in the previous year, but larval growth was reduced on previously insect-damaged branches. With mountain ash just physical damage per se reduced the performance of Epirrita larvae. On Salix phylicifolia there were no significant differences in the growth or survival of Epirrita on untreated control bushes and on bushes with partial larval damage during the previous year. Among untreated control trees the growth and survivorship of Epirrita were higher on fast-growing willow and bird cherry than on the slow-growing mountain birch. Mountain birch and mountain ash, the two deciduous tree species adapted to nutrient-poor soils, showed delayed inducible resistance triggered by defoliation (artificial or insect-made). This supports the hypothesis that delayed inducible resistance may be a passive response due to nutrient-stress caused by defoliation. On the other hand, the additional increase in the resistance of mountain birch triggered by specific cues from insects suggests that this response may be an evolved defense against leaf-eating insects.     

Ultrastructure of cells in the cambial region during winter hardening and spring dehardening in Salix dasyclados Wim. grown at two nutrient levels

Summary The ultrastructure of cells in the cambial region of Salix dasyclados Wim. (clone 78056) was studied during the development of winter hardiness and the onset of cambial activity in spring. Plants were grown at relative growth rates (R_G) of 8% and 12% respectively, resulting in different nitrogen content in the stems. Frost hardiness of the plants was estimated by standardized freezing tests. Plants with a higher nitrogen status ceased growth later and started re-growth earlier in spring than plants with lower nitrogen content. Differences in ability to withstand low temperatures during autumn and spring were found between plants grown in the two nutrient treatments. During the development of frost hardiness in the autumn, the number of meristematic cells in the cambial region decreased. The cessation of meristematic activity was accompanied by cell wall thickening and ultrastructural changes in the cells. Frost hardiness increased from the ability to survive -6° C in October to survival of -80° C at the beginning of December. From November to February the cambial region comprised a layer of 2–3 thick-walled cells with conspicuous ultrastructural features. Starch accumulated in plastids in September, decreased during November to March and then increased again in accordance with changes of frost hardiness. Onset of cambial activity began between the end of March and the beginning of April, as shown by increased vacuolization of meristematic cells and mitotic activity. By April, the starch content had increased and lipolysis was observed. Frost hardiness had decreased, and plants with low and high nitrogen content were able to survive -15° C and -10° C, respectively. After budburst, all axillary shoot parts were damaged at temperatures below-3° C.Abbreviations Cz cambial zone - ER endoplasmic reticulum - Lb lipid body - m mitochondrion - Mm multimembraneous structure - Ms myelin-like structure - n nucleus - p plastid - Pb protein body - Pc pit cells - Ph phloem - Pd plasmodesmata - Pl plasmalemma - pl protective layer - Pt plasmatubules - Pw primary wall - Sw secondary wall - s starch - t tannins - v vacuole - K vessel - X xylem - Scale bars 1 urn     

Increase in cereal stem borer populations through partial elimination of natural enemies

An insecticide exclusion method was used to evaluate the effect of parasitoids on level of infestation by the stem borers, Busseola fusca (Fuller) and Chilo partellus (Swinhoe), in grain sorghum. In field trials conducted at Brits and at Delmas, South Africa, a selective organophosphate insecticide, dimethoate, was applied twice weekly at each site to three subplots whereas three other identical subplots served as controls. Twelve plants were randomly selected from each subplot at weekly intervals and removed from the field. In the laboratory all plants were dissected to record borer infestation. In order to determine parasitism levels egg batches were kept in Petri dishes and all borer larvae and pupae were kept individually in vials until either parasitoids or moths emerged. At Brits ca. 97% of borers were C. partellus and 3% B. fusca, whereas at Delmas 37.5% were C. partellus and 62.5% B. fusca. The most abundant parasitoids of B. fusca were Cotesia sesamiae (Cameron) and Bracon sesamiae Cameron. The dominant parasitoids of C. partellus at both sites were C. sesamiae, Stenobracon spec., Dentichasmias busseolae Henrich and Pediobius furvus (Gahan). No egg parasitoids were found. At both sites, infestation levels in the sprayed plots were significantly higher than in the untreated plots. On the other hand, parasitism levels of borers in the unsprayed plots were significantly higher than in the treated plots. It was concluded that the higher infestation level of sorghum by stem borers in the sprayed plots was because of partial elimination of parasitoids and possibly other natural enemies by the pesticide.     

Season long intraplant epizootics of entomopathogens,Beauveria bassiana andNosema pyrausta,in a corn agroecosystem

Intraplant epizootics of entomopathogens,Beauveria bassiana (Balsamo) Vuillemin, andNosema pyrausta (Paillot) were studied in a corn,Zea mays L., agroecosystem. Egg masses of the European corn borer,Ostrinia nubilalis (Hübner), infected withN. pyrausta were placed on midwhorl-stage corn plants. Conidia ofB. bassiana were applied in an aqueous suspension. Frass from the initial insects remaining within the plants was contaminated with sufficientN. pyrausta spores to infest 80% of the filial generation in each year of a 2-yr study. Viability ofN. pyrausta within the frass was monitored throughout the winter. Potential for impact of this inoculum on the filial generation is discussed. Conidia from cadavers of the European corn borer that were killed by the initial inoculum ofB. bassiana and/or conidia from the initial inoculum ofB. bassiana significantly reduced tunneling by the filial generation of the European corn borer. However, neither the concentration ofB. bassiana nor the age of the larvae exposed toB. bassiana, had any significant (P<.05) effect on tunneling by the 2nd-generation larvae. This paper reports the results of research only. Mention of a pesticide in this paper does not constitute a recommendation for use by the U.S. Department of Agriculture or cooperators, nor does it imply registration under FIFRA as amended.     

阿尔山落叶松主要蛀干害虫的种群空间生态位

对阿尔山落叶松主要蛀干害虫的种群生态位进行了研究,结果表明:在落叶松衰弱立木上,生态位宽度以落叶松八齿小蠹最高,在中龄和老龄树上分别达到0.5782、0.5498,在落叶松中龄和老龄枯死立木上,白带长角天牛的空间生态位宽度分别达到0.5143、0.6294,分布较衰弱木广,而云杉大黑天牛空间生态位宽度在衰弱和枯死立木上都最低。落叶松立木上的空间生态位重叠指数以落叶松八齿小蠹对其他3种优势天牛偏高,天牛之间的空间生态位相似性比例指数均较高且差距较小,说明4种害虫对空间生态位的占据有很大相似程度。4种害虫的空间种间竞争系数均很大,说明对空间和资源的竞争非常激烈,在这种情况下4种害虫能够共存,根本原因是由于取食部位的分化。     

Development of transgenic sorghum for insect resistance against the spotted stem borer (Chilo partellus)

Transgenic sorghum plants expressing a synthetic cry1Ac gene from Bacillus thuringiensis (Bt) under the control of a wound-inducible promoter from the maize protease inhibitor gene (mpiC1) were produced via particle bombardment of shoot apices. Plants were regenerated from the transformed shoot apices via direct somatic embryogenesis with an intermittent three-step selection strategy using the herbicide Basta. Molecular characterisation based on polymerase chain reaction and Southern blot analysis revealed multiple insertions of the cry1Ac gene in five plants from three independent transformation events. Inheritance and expression of the Bt gene was confirmed in T₁ plants. Enzyme-linked immunosorbant assay indicated that Cry1Ac protein accumulated at levels of 1–8 ng per gram of fresh tissue in leaves that were mechanically wounded. Transgenic sorghum plants were evaluated for resistance against the spotted stem borer (Chilo partellus Swinhoe) in insect bioassays, which indicated partial resistance to damage by the neonate larvae of the spotted stem borer. Reduction in leaf damage 5 days after infestation was up to 60%; larval mortality was 40%, with the surviving larvae showing a 36% reduction in weight over those fed on control plants. Despite the low levels of expression of Bt -endotoxin under the control of the wound-inducible promoter, the transgenic plants showed partial tolerance against first instar larvae of the spotted stem borer.     

Effects of soybean proteinase inhibitor on development, survival and reproductive potential of the sugarcane borer, Diatraea saccharalis

One approach that can be employed in integrated pest management is the use of proteins with antinutritional effects on insect metabolism and development. The antimetabolic properties of soybean proteinase inhibitor (SPI) on growth of neonate larvae of the sugarcane borer, Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) have been evaluated. When incorporated into an artificial diet at 0.5% (w/w), SPI retarded growth rate and development of larvae when compared with larvae fed on artificial diet alone. However, larval survival was not significantly affected. The purpose of our research was to calculate demographic statistics for the sugarcane borer reared on diet either with or without semi-purified extract of SPI. Net reproductive rate (R ₀), instantaneous rate of increase (r _m), combined age-specific survivorship (l _x) and age specific fecundity (m _x) provide information about population growth potential. These parameters were measured in order to determine the effects of the proteinase inhibitor on the insect's population dynamics. The observed differences would potentially translate into large reductions in population growth, indicating a potential value of using SPI for protecting sugarcane plants against damage by the sugarcane borer.     

Partial age-specific life tables for Monochamus titillator in Dendroctonus frontalis infested loblolly pines

Partial age-specific life tables were constructed for Monochamus titillator(Fabricius) (Coleoptera: Cerambycidae) in Dendroctonus frontalisZimmermann (Coleoptera: Scolytidae) infested loblolly pine (Pinus taedaL.) trees. Successive life stages including egg, early larvae, mid-stage larvae, late larvae, and adult emergence were sampled within six sample trees. Generation mortality ranged from 60.94% to 98.61% in sample trees. Highest mortality typically occurred to eggs and mid-stage larvae. Possible mortality factors included resinosis, predaceous beetles, parasitoids, and woodpeckers. Dendroctonus frontalisbrood stages were determined for consecutive M. titillatorsampling. Monochamus titillatorand D. frontaliscoexisted and likely interacted in the phloem of host trees for at least 20 days.