Leaf Clusters Research Articles

Evaluation of Insecticides Against Lepidopterous Pests During Bloom on Blueberries, 1996

Abstract This study was conducted in a ‘Bluecrop’ blueberry field near Whitesbog, NJ. Blueberry bushes were approximately 5 ft tall and spaced 9 X 4 ft apart. Treatments were arranged in a RCB design, replicated 5 times with each replication consisting of 6 bushes in 2 rows. Two unsprayed rows between blocks and 8 unsprayed bushes between treatments within a block served as buffers. Insecticides were applied with a CO2 pressurized Model T backpack sprayer (R & D sprayers) equipped with a Tee Jet hollowcone (4 VS) nozzle calibrated to deliver 30 gal/acre at 40 PSI. Insecticides were applied twice on 14 May and 24 May approximately at 40 and 80% bloom, respectively. Spray adjuvants, Nu-Film 17 (4 oz/acre) and Latron B-1956 (0.12% v/v) were included in all B.t. and Confirm treatments, respectively. GM eggmasses were obtained from USDA-APHIS facility at Otis Air Base in Cape Code, MA, to augment larval populations in the field plots. Eggmasses were stapled to the bush on 4 May at the rate of one eggmasses per bush. Eggmasses began hatching on 6 May and larvae were well distributed on the bushes within a week after hatching. Larval populations were assessed by sampling 25 clusters from each of 4 randomly selected bushes/replicate for a total of 100 leaf and flower clusters/replicate on 13 May (pretreatment count), and 24 May and 1 Jun (post-treatment counts). Leaf and flower clusters were randomly selected from the top, middle and bottom thirds of each bush.

Evaluation of Insecticides Against Lepidopterous Pests During Bloom on Blueberries, 1995

Abstract This study was conducted in a ‘Bluecrop’ blueberry field in full production near Whitesbog, NJ. Blueberry bushes were approximately 5 ft tall and spaced 9X4 ft apart. Treatments were arranged in a RCB design, replicated 5 times with each replication consisting of 6 bushes in 2 rows. Two unsprayed rows between blocks and 5 unsprayed bushes between treatments within a block served as buffers. Insecticides were applied with a Mighty Mac model PS-322T garden sprayer equipped with a handgun calibrated to deliver 200 gal/acre at 75 PSI. Insecticides were applied once on 16 May approximately at 50% bloom. GM eggmasses were obtained from USDA-APHIS facility at Otis Air Base in Cape Cod, MA, to augment larval populations in the field plots. Eggmasses were stapled to the bush on 3 May at the rate of 1 eggmass per bush. Eggmasses began to hatch on 6 May and larvae were well distributed on the bushes within a week after hatching. Larval populations were assessed by sampling 25 clusters from each of 4 randomly selected bushes/replicate for a total of 100 leaf and flower clusters/replicate on 15 May (pre-treatment count) and 26 May (post-treatment count). Leaf and flower clusters were randomly selected from the top, middle and bottom thirds of each bush.

World War II's most highly decorated US physician.

To the Editor. —Recent commemoration of the Normandy invasion makes it timely to call attention to John Erbes, MD, who was the most highly decorated US physician in World War II. Dr Erbes, a 1939 graduate of the University of Nebraska College of Medicine, was a battalion surgeon in the Second Armored Division and saw front-line duty in French Morocco, Tunisia, Sicily, Normandy, northern France, Belgium, and Germany. His awards include the Distinguished Service Cross, the Silver Star with three Oak Leaf Clusters, and the Bronze Star, as well as two unit awards. The latter include the Presidential Unit Citation, given to his battalion for breaking the Siegfried line near Aachen on October 4, 1944, and the Belgian Fourragere, given for the division's decisive role in turning back the German spearhead at its deepest penetration in the Battle of the Bulge. This was the first time the latter award was

World War II's Most Highly Decorated US Physician

<h3>To the Editor.</h3> —Recent commemoration of the Normandy invasion makes it timely to call attention to John Erbes, MD, who was the most highly decorated US physician in World War II. Dr Erbes, a 1939 graduate of the University of Nebraska College of Medicine, was a battalion surgeon in the Second Armored Division and saw front-line duty in French Morocco, Tunisia, Sicily, Normandy, northern France, Belgium, and Germany. His awards include the Distinguished Service Cross, the Silver Star with three Oak Leaf Clusters, and the Bronze Star, as well as two unit awards. The latter include the Presidential Unit Citation, given to his battalion for breaking the Siegfried line near Aachen on October 4, 1944, and the Belgian Fourragere, given for the division's decisive role in turning back the German spearhead at its deepest penetration in the Battle of the Bulge. This was the first time the latter award was

Insecticide Evaluations Against Foliar and Fruit Feeding Insects on Blueberries, 1994

Abstract This experiment was conducted in a recently abandoned ‘bluecrop’ blueberry field in full production, near Whitesbog, NJ. Blueberry bushes were approximately 5 ft tall and spaced 9 × 4 ft apart. Treatments were replicated 6 times in a randomized complete block design with each replicate consisting of 6 bushes in 2 rows. There were 2 unsprayed rows between blocks, and 3 unsprayed bushes between treatments within a block that served as buffer. Insecticides were sprayed to runoff with a Mighty Mac model PS-322T garden sprayer equipped with a Hamilton handgun operated at 200 psi. Approximately 1.25 to 1.5 gal of spray solution was applied per replicate (250-300 gal/acre). Insecticides were applied 3 times beginning petal-fall on 31 May, 10 June, and 23 June. Data were collected from 100 leaf and fruit cluster (CL) samples (25 clusters × 4 randomly selected bushes/replicate) on 8 June and 14 June. Samples consisted of 40 fruit clusters (10 fruit clusters × 4 randomly selected bushes/replicate) on 1 July. A leaf or fruit cluster was considered damaged if at least 1 leaf or fruit in that cluster was injured.

The effect of short-range host odor stimuli on host fruit finding and feeding behavior of plum curculio adults (Coleoptera: Curculionidae)

In laboratory assays, we investigated responses of female plum curculios (PCs),Conotrachelus nenuphar (Herbst), to host and nonhost fruit or leaf odor when PCs were crawling on experimental tree branchlets or twigs. In choice tests where test specimens were hung from the ends of a wooden crosspiece, PCs made significantly more visits to host plum fruit than to plum leaves, nonhost tomato fruit, wax models of plum fruit, or blanks (wire). In similar tests, PCs made significantly more visits to plum leaves compared to nonhost maple leaves or to blanks. PCs in test chambers that contained host or nonhost odor were significantly more prone to feed on wax plum models in the presence of odor from host fruit or host leaves compared to odor from nonhost fruit or leaves or a water blank. In choice tests offering alternating cluster types on an apple branchlet, PCs visited leaf clusters bearing a host apple fruit more than leaf clusters without a fruit. In tests to assay the distance at which PCs can detect an individual host fruit, PCs crawled from the central stem of an apple branchlet onto a side stem significantly more often when an apple fruit on a side stem was hung 2 cm from the central stem compared to 4 or 8 cm away. Our combined results suggest that PCs use host fruit odor to locate host fruit at close range.

Leafroller oviposition on larval host plants

Caged greenheaded leafroller (Planotortrix excessana (Walker)) (Lepidoptera: Tortricidae) and lightbrown apple moth (Epiphyas postvittana (Walker)) (Lepidoptera: Tortricidae) adults were provided with the leaves of known larval host plants to determine the relative amount of oviposition on the different hosts. Relative to apple leaves, lightbrown apple moth oviposited fewer eggs on narrow-leaved plantain (Plantago lanceolata L.), and blackberry (Rubus strigolosus agg.) and equal numbers on poplar (Populus nigra L.). Greenheaded leafrollers laid more eggs on poplar leaves than on apple leaves. Close examination of the likely factors determining oviposition sites revealed that hairs on the dorsal leaf surface could affect the choice of oviposition sites. Lightbrown apple moths therefore tended to oviposit more frequently on the less hairy mature leaves of apple shoots compared to more hairy, emerging leaves which had a greater density of dorsal surface leaf hairs. Arrangement of host plant leaf clusters may...

Pink Spray for Pear Thrips Control on Apple, 1989

Abstract Five insecticides were compared for efficacy in controlling pear thrips on adults on 19-yr-old semidwarf 'McIntosh' trees at Hamden, Conn. Single-tree plots were arranged in a randomized complete block design, with 5 replicates/treatment. Diazinon, Guthion, Malathion, Vydate, and water (control) were applied dilute to runoff on 3 May (early pink) with a Chapin Compressed Air Sprayer Model 152. Safer Insecticidal Soap was applied with a trigger sprayer attached to a plastic ready to use bottle. The trees received one dormant oil and one Cyprex application before the experiment. Thrips density was measured prior to treatments on 3 May and 2 days after them on 5 May (pink) by randomly collecting 10 leaf clusters with flowers/tree at chest height and counting adults in the laboratory. Dry, fair weather prevailed throughout the test.

Sexual Selection and Assortative Mating in Subdivided Populations of the Thrips Elaphrothrips tuberculatus (Insecta: Thysanoptera)

AbstractThis study presents four years of data on size‐related mating patterns in Elaphrothrips tuberculatus, a subsocial thrips inhabiting subdivided populations (clusters of hanging dead oak leaves) that vary in sex ratio, operational sex ratio (ratio of males to females guarding eggs), and number of adults. Laboratory observations, experimental removals of guarding males, and field collections showed that: (1) males guard mates after copulation, (2) guarding males are larger than non‐guarding males, and (3) large male mating advantage is caused by male fighting. The populationwide intensity of sexual selection for large male body size varied substantially among years, reflecting yearly differences in the sex ratio and operational sex ratio. Among local populations (leaf clusters), the sexual selection intensity was correlated with the operational sex ratio in each year, and with the sex ratio in three of four years. Males and females mated assortively for size (fore‐femora length) in 1986, but not in 1983, 1984, or 1985. Assortative mating in 1986 was attributed to Darwin's (1871) mechanism for sexual selection in monogamous species: in this year alone, there was a highly significant tendency for large females to initiate breeding earlier than smaller females and strong directional selection for large male body size. Population subdivision affects mating patterns of E. tuberculatus by: (1) creating single‐male populations where male size does not affect mating success, (2) promoting high sexual selection intensities, relative to a continuous population, when the population‐wide sex ratio is female biased, and (3) constraining the size covariation between paired males and females.

Feeding and the epiphyte food resources of gastropods living on leaves of the SeagrassAmphibolis griffithii in south-western Australia

Abstract This paper reports the radula structure and diets of trochid ( Thalotia conica, Prothalotia lehmanni) and columbellid (Pyrene bidentata) gastropods that reside amongst the terminal leaf clusters of the seagrass, Amphibolis griffithii, in shallow, subtidal regions of south-western Australia. Both trochids possessed similar rhipidoglossan radulae that swept diatoms, small encrusting coralline algae and other organisms from the seagrass leaves. Pyrene bidentata used similar food resources but also consumed some larger food fragments (e.g. hydroid colonies) with its rachiglossan radula. Snail diets most closely reflected the range and abundance of epiphytes on leaves in summer. During particularly the winter, certain diatoms were disproportionately present in snail diets, either through active food selection or because some diatoms were patchily distributed on leaves. Although unidentifiable materials accounted for about 20–35% by volume of food present in snail stomachs, our data support the view th...

Shoot elongation, leaf demography and bud formation in relation to branch position on Larix laricina saplings

Shoot development was investigated on branches of Larix laricina (Du Roi) K. Koch trees growing in their 8th year in two plantations and in a natural stand approximately 12 years old. Expansion of throughout-crown series of short and long shoots was measured weekly, and later colour change and natural fall of leaves were assessed. Similar shoots were collected at intervals and dissected, the long shoots by 25-leaf segments. Leaf area and weight, as well as time of bud formation, were determined. Increasing acropetal trends were evident in time to bud burst: duration of short-shoot leaf-cluster expansion; size of leaf clusters and number, area and weight of leaves per cluster; duration and rate of long-shoot elongation; number, area and weight of leaves on long shoots; time to terminal-bud formation on long shoots. Along each long shoot, stem and leaf elongation and lateral-axis formation progressed acropetally. Lateral axes were most numerous on second to fourth 25-leaf segments. On longer shoots, some axes in middle segments developed as sylleptic short shoots rather than as lateral buds. Leaves of short shoots and basal leaves on long shoots turned yellow and abscissed sooner than axial leaves on long shoots. Colour change and loss among axial leaves were acropetal along shoots and up the crown. Thus, last-formed leaves, in axils of some of which lastformed lateral buds occurred, were held longest.

The development of an artificial, Amphibolis-like seagrass of complex morphology and preliminary data on its colonization by epiphytes

A method is described for the construction of artificial seagrass plants whose stems and terminal leaf clusters resemble those of Amphibolis spp. In preliminary trials, the artificial seagrasses were deployed and withstood at least 40 days immersion in a shallow, subtidal Amphibolis meadow on a moderate energy coastline in south-western Australia. In trials conducted between August (winter) and April (autumn), the artificial seagrasses became colonized with numerous algae and invertebrates that were present as epiphytes on living Amphibolis within the same meadow. Recruitment of epiphytes was usually rapid, and a number of species became fertile within the trial period. The artificial seagrasses described in this study represent a valuable tool for the assessment of epiphyte recruitment and growth on seagrasses that possess perennial stems and branches, and transient leaves within terminal clusters.

Development of Dead Leaf Foraging in a Tropical Migrant Warbler

The Worm—eating Warbler (Helmitheros vermivorus), a neotropical migrant bird, specializes during the nonbreeding season in searching dead curled leaves that hang in the understory of tropical forest. How such a specialization might develop in individual warblers was investigated in an experimental study of hand—raised birds. In these experiments I measured the preference that juvenile warblers showed in visiting various micro—habitats. The experiments produced the following results. (1) Juvenile warblers, prior to any self feeding, showed a highly stereotypic ranking of preference for exploring different "microhabitats," visiting dead leaf clusters nearly three times as frequently as the next most preferred microhabitat types. Such as strong stereotyped order of preference was not found in similar experiments using the ecologically less specialized Carolina Chickadee (Parus carolinensis). (2) The same individual Worm—eating Warblers showed consistent preferences for visiting certain microhabitats at the age when they would normally be arriving in the tropics. However, dead curled leaves were no longer strongly preferred over other foliage types. (3) With other factors held constant, Worm—eating Warblers spent significantly more time manipulating curled versus uncurled foliage, but did not respond to either texture or color differences between live and dead leaves. (4) Worm—eating Warblers spent over half of their active time manipulating substrates, particularly foliage; this activity varied little among birds and among experiments and was also not extinguishable through elimination of food reinforcement. (5) Preference for a particular foliage type (including dead leaves) increased with positive reinforcement with food. These results suggest that young Worm—eating Warblers enter the world with a rigidly determined preference for dead leaves during the period of unreinforced exploration. I suggest that this preference is relaxed when birds are self—feeding because, with their highly manipulative behavior, they can readily track changes in abundance of dead—leaf and live—leaf arthropods. In this case, a consistent and apparently species—typical preference for dead curled leaves appears to be learned.

Foraging pattern of pine siskins and its influence on winter moth survival in an apple orchard.

Foraging by migratory pine siskins in an apple orchard infested with varying densities of winter moth was observed, and winter moth mortality in the presence and absence of birds was recorded. Time spent foraging in a tree and number of birds foraging per tree was positively related to larval density but number of larvae removed per leaf cluster or per unit time was not. Level of defoliation was a better predictor of the number of clusters searched per tree than was prey density. Despite poor predictability in allocation of search effort with respect to prey density, siskins acted as a source of strong compensatory mortality on the winter moth population.

Variation in clove (Syzygium aromaticum) germplasm in the moluccan islands

One hundred clove trees from a total of 34 wild and cultivated populations, mainly in the north and central Moluccas, were examined for morphological variation. Data were evaluated using cluster analysis, principal co-ordinates analysis and canonical variates analysis. Considerable morphological variation was evident and was largely attributable to between-population sources. There was more variation among wild cloves than among cultivated populations. Several of the cultivated populations were shown to be morphologically distinct. Flower bud characters were most valuable in distinguishing between populations; leaf and flower bud cluster characters were also useful. Permanent germplasm collections are needed to conserve variation.

Schizoneura gondwanensis feistmantel da formação Rio do Rasto (Bacia do Paraná, permiano superior) no estado do Paraná e no norte do estado de Santa Catarina

Specimens of Schizoneura gondwanensis are here described from 13 new outcrops of the Rio do Rasto Formation (Passa Dois Group, Paraná Basin, Upper Permian) in Paraná State and northern Santa Catarina State. This species was previously known in Brazil from only two other locaiities of the same formation. The foliage shoots, preserved as impressions in red and gray mudstones, siltstones and fine sandstones, generally occur as fragments, which may, however, exhibit well-preserved details such as possible structures of the mesophyll and epidermis, only very rarely recognized in other Gondwana specimens of Schizoneura. The fossils also corroborate Feistmantel's observations made in 1880, but overlooked by many later authors, regarding the embracing of the leaf clusters at the nodes, commissural lines, veins, etc. Although the leaf clusters at one outcrop are oblong-oval and not oval-lanceolate as at the other outcrops, ali are tentatively considered as belonging to the same species. Several of the leaf clusters of S. gondwanensis present ruptures along the commissural lines, here interpreted as the result of taphonomic processes or, possibly, environmental factors that affected the living plant. Ontogenetic aspects of Schizoneura and comparisons with Cathaysian representatives of this genus are also discussed. S. gondwanensis thus has a much broader geographical range in Brazil than previously thought and, consequently, can now be considered as one more important element of Rösler's Taphoflora E

Three New Species of Solanum Section Geminata (G. Don) Walp. (Solanaceae) from Panama and Western Colombia

Three New Species of Solanum Section Geminata (G. Don) Walp. (Solanaceae) from Panama and Western Colombia

Preformation of root primordia in shoots and root morphogenesis in Salix viminalis

Root primordia are formed in the stems of Salix viminalis L. during normal growth. Some of these primordia are produced at definite sites in the nodes. The initiation and early structural and ultrastructural development of the nodal primordia were studied in young shoots. In the fourth node below the terminal leaf cluster some parenchyma cells situated at the lateral leaf gaps formed a small group of initial cells. Derivatives of the newly formed interfascicular cambium added cells to that group, in which later on cell divisions in various directions occurred resulting in the formation of a root primordium. Root morphogenesis was studied in cuttings from one‐season‐old stems. The cells in the dormant primordia contained many lipid bodies but only a small amount of starch. After the cuttings had been 24 hours in water starch was accumulating in the plastids and lipid bodies were seen in the vacuoles. 48 hours after activation cell divisions occurred throughout the primordia and a layered apical mer‐istem was organized. After 96 hours a root cap with amyloplasts was formed and the procambium was well developed. The amyloplasts were sedimented in response to gravity. After six days the first roots were ready to emerge from the stems. Their root caps had a well developed columella and endodermal and pericyclic cells were recognizable.

Host selection byBlepharipa pratensis (Meigen), a tachinid parasite of the gypsy moth,Lymantria dispar L.

The host selection process ofBlepharipa pratensis (Meigen), a tachinid parasite of the gypsy moth,Lymantria dispar L., was investigated. Once in the host's habitat, and following contact with a recently damaged leaf edge (cut, torn, eaten), the fly orients perpendicular to the edge and moves back and forth with the front tarsi grasping the damaged edge. Oviposturing (oviposition intention) may occur. Leaf exudates appear to arrest the fly on the leaf and increase tarsal examination (searching). If an edge of a gypsy moth-eaten leaf is contacted, oviposition usually occurs. Significantly more eggs are laid when host-browsed foliage is encountered, compared to mechanically cut or damaged foliage, indicating response to a cue left by the host during feeding. The number of host-damaged leaf clusters in an area significantly enhances oviposition there; in field-cage tests, significantly more eggs (7911) were laid in simulated-crown areas with all clusters browsed, compared to the adjacent areas containing 1/2 browsed (4200 eggs) and undamaged clusters (2209 eggs). A host selection sequence is suggested and discussed.

Distribution of Phytophagous Mirids (Hemiptera: Miridae) on Apple Trees in Relation to Habitat Availability 1

Habitat preferences, within apple trees, of nymphal and adult Lygocoris communis (Knight), Lygidea mendax Reuter, Campylomma verbasci (Meyer), and Heterocordylus malinus Reuter were investigated with respect to availability of leaf clusters and fruit clusters. The younger nymphs of L. communis, C. verbasci , and H. malinus showed a preference for branches with more fruit clusters. Older nymphs, except those of L. communis, and adults showed no significant habitat preferences. Since younger nymphs are largely responsible for direct damage to apples, their habitat preference should be recognized during sampling for population monitoring purposes.