SPATIAL DISTRIBUTION OF ADULTS OFOOENCYRTUS KUVANAE(HYMENOPTERA: ENCYRTIDAE), AN EGG PARASITE OFLYMANTRIA DISPAR(LEPIDOPTERA: LYMANTRIIDAE)

1982 ◽  
Vol 114 (12) ◽  
pp. 1109-1120 ◽  
Author(s):  
M. W. Brown ◽  
E. Alan Cameron
Keyword(s):  
Spatial Distribution ◽  
Gypsy Moth ◽  
Tree Species ◽  
Small Sample ◽  
Egg Mass ◽  
Parasite Abundance ◽  
Egg Masses ◽  
Positive Correlation ◽  
Wide Range ◽  
Mass Volume

AbstractThe spatial distribution of adultOoencyrtus kuvanae(Howard) (Hymenoptera: Encyrtidae) was examined in central Pennsylvania during 1978–1980. Data were gathered over a wide range of gypsy moth (Lymantria dispar(L.) (Lepidoptera: Lymantriidae)) densities and from all phases of population growth. There was a linear relationship between the log variance and log mean, fitting Taylor's Power Law with a power of 1.27. The degree of aggregation inO. kuvanaepopulations, as measured by the variance-to-mean ratio, was correlated positively with the abundance of the parasite, and was independent of host density. Aggregation was believed to result from the habit of the female parasite ovipositing repeatedly on the same egg mass, and the resultant progeny emerging synchronously. Behavior and density ofO. kuvanaepopulations were found to depend upon the gypsy moth population condition, i.e., low, rising, high stable, outbreak, or collapsed. The frequency distribution ofO. kuvanaepopulations fit the Poisson at densities less than 0.2 parasite adult per egg mass, a condition which occurred early and late (July, November) in the season, and the negative binomial above this density; a few distributions fit the log normal. The data were also analyzed using analyses of variance (multivariate and univariate), correlation, and regression techniques. All main effects, i.e., study area, host egg mass volume, egg mass height from the ground (within the 0–2 m sampling universe), aspect of the egg mass on the tree, and tree species, were important in explaining the variance in parasite abundance; study area differences were the most important. The effects of aspect and tree species were explained on the basis of small sample sizes, and not studied further. There was a positive correlation between host egg mass volume (= size) and parasite abundance. There was also a positive correlation between the height of the egg mass and parasite abundance during the summer; however, this relationship became negative by late fall. This seasonal change in vertical distribution was attributed to the tendency ofO. kuvanaeto be closer to the ground where they overwinter. Variation in adult abundance was generally greater among gypsy moth egg masses on different trees than among egg masses on the same tree, except at low parasite densities. This was attributed to the parasites searching for egg masses on one tree before dispersing to another.

Augmenting Nucleopolyhedrovirus Load in Gypsy Moth (Lepidoptera: Lymantriidae) Populations with Egg Mass Treatments

2003 ◽  
Vol 38 (2) ◽  
pp. 300-313 ◽  
Author(s):  
R. E. Webb ◽  
G. B. White ◽  
K. W. Thorpe
Keyword(s):  
Gypsy Moth ◽  
Early Treatment ◽  
Adult Emergence ◽  
Field Studies ◽  
Host Population ◽  
Egg Mass ◽  
Moth Population ◽  
Egg Masses ◽  
Entomophaga Maimaiga ◽  
Virus Dose

Previous observations show that gypsy moth, Lymantria dispar L., mortality induced by the fungus Entomophaga maimaiga Humber, Shimazu & Soper is quickly manifested as host population density increases. However, the gypsy moth nucleopolyhedrovirus (LdMNPV) lags behind the rebounding gypsy moth population. In this study, egg masses were contaminated with virus to successfully augment LdMNPV in gypsy moth populations in Virginia. Laboratory bioassays determined the approximate LdMNPV dose to apply to egg masses with and without the addition of the virus enhancer Blankophor BBH to the spray mixture. The highest dose of virus (5.3 × 105 PIBs/mL) tested without Blankophor BBH gave 82.3% mortality. Mortality for this virus dose increased to 91.8% when 1% Blankophor BBH was added. Field studies established that application of virus at an earlier date (04 April) was as efficacious as an application made at a later date (12 April); this study also included a further assessment of the addition of Blankophor BBH to the spray mixture. While application of LdMNPV + Blankophor BBH resulted in faster kill, levels of kill were similar (88.0% for early treatment and 78.8% for later treatment for virus applied alone versus 87.8% for early treatment and 89.1% for later treatment for virus + Blankophor BBH). However, a higher than expected number of cadavers in the LdMNPV + Blankophor BBH treatments had few or no polyhedral inclusion bodies (PIBs). Finally, virus infection resulting from the application of LdMNPV to pupae in June 1998 was compared with infection levels seen after the application of virus to egg masses in April 1999. The April 1999 treatment to egg masses clearly resulted in a higher kill of emerging larvae (=79.3% mortality) compared to the June 1998 treatment to female pupae (with virus incorporated into the egg masses laid by females after adult emergence) (=13.7% mortality). The virus was recovered season-long from larvae collected from populations in the treated plots (but not from control plots), indicating within season spread.

Nematode resistance of rape-radish chromosome addition lines

Nematology ◽  
2010 ◽  
Vol 12 (2) ◽  
pp. 269-275 ◽  
Author(s):  
Herbert Peterka ◽  
Holger Budahn ◽  
Shao Song Zhang ◽  
Jin Bin Li
Keyword(s):  
Dominant Gene ◽  
Nematode Resistance ◽  
Heterodera Schachtii ◽  
Egg Mass ◽  
Addition Line ◽  
Addition Lines ◽  
Egg Masses ◽  
Chromosome Addition ◽  
Chromosome Addition Lines ◽  
Wide Range

Abstract Oilseed radish is resistant to the beet cyst nematode (Heterodera schachtii Schmidt), interrupting the life cycle of this sedentary pathogen by blocking feeding cell development in the root. A complete set of nine disomic rape-radish chromosome additions, a to i, derived from a susceptible rapeseed parent as recipient and a resistant radish as chromosome donor, was assayed for nematode resistance. The addition line d exhibited the resistance level of the radish parent, confirming previous results that radish chromosome d carries a dominant gene, Hs1Rph, for nematode resistance. It was investigated if Hs1Rph is effective against a further important sedentary parasite, the northern root-knot nematode Meloidogyne hapla. The set of chromosome addition lines and the parents, rape and radish, were inoculated with second-stage juveniles (J2) of M. hapla and the plant reaction was evaluated by counting the number of egg masses per root system. By contrast to the situation in H. schachtii, the radish parent as well as addition line d showed no resistance against M. hapla and was even more susceptible than rape. It was concluded that the resistance gene Hs1Rph, which inhibits syncytium development of H. schachtii, is ineffective against M. hapla, a nematode inducing giant cell formation. Most added radish chromosomes significantly changed the number of egg masses in the recipient rape towards higher susceptibility. Two chromosomes enhanced the egg mass number beyond that of the chromosome donor radish. However, one radish chromosome decreased the egg mass production in the corresponding addition line below that in rape. This wide range of effects of the individual radish chromosomes in the rape background indicates a quantitative inheritance of host suitability to M. hapla and a complex interaction between the pathogen and radish.

Influence of burlap-band colour on larval, pupal, and egg-mass counts of Lymantria dispar (Lepidoptera: Lymantriidae)

2003 ◽  
Vol 135 (6) ◽  
pp. 869-877
Author(s):  
David B. Roden
Keyword(s):  
Gypsy Moth ◽  
Lymantria Dispar ◽  
Field Experiments ◽  
Quercus Rubra ◽  
Egg Mass ◽  
Egg Masses ◽  
Band Position ◽  
The Mean ◽  
Pupation Site ◽  
Selection Of

AbstractThis paper describes the effect of the colour of burlap bands (black versus naturally coloured or tan burlap) affixed to red oak, Quercus rubra (L.) (Fagaceae), and how it influences selection of larval resting site, pupation site, and egg-mass counts of gypsy moth, Lymantria dispar (L.). In field experiments with half black and half tan burlap bands, the mean number of larvae, pupae, and egg masses were significantly greater under the black section of burlap. Individual burlap bands composed of either black or tan burlap affixed to separate trees produced similar significant results for larvae and pupae. When two burlap bands composed of opposite colours (black versus tan) were affixed to the same tree, significantly more larvae were found under the upper band, regardless of colour. In contrast, pupa and egg-mass densities were significantly greater under black bands, regardless of band position.

Destruction of Gypsy Moth Egg Masses (Using Surfactants, Detergents, Oils or Conventional Insecticides) for Quarantine and Community Action Programs2

1994 ◽  
Vol 29 (3) ◽  
pp. 305-317
Author(s):  
R. E. Webb ◽  
W. H. McLane ◽  
J. A. Finney ◽  
L. Venables ◽  
G. B. White ◽  
...  
Keyword(s):  
Soybean Oil ◽  
Gypsy Moth ◽  
Agricultural Research ◽  
Community Action ◽  
Egg Mass ◽  
Mass Destruction ◽  
Egg Masses ◽  
Highly Active ◽  
Methods Development ◽  
Development Center

A series of studies were conducted, beginning in 1976, at the Otis Methods Development Center, Otis ANGB, MA, and beginning in 1982 at the Beltsville Agricultural Research Center, Beltsville, MD, to evaluate surfactants, detergents, oils, and insecticides as egg mass destruction agents for use in quarantine and community action programs. Surfactants, oils, and detergents tended to be more active when applied in the fall, while conventional insecticides were generally more active when applied in the spring. Some products, especially soybean oil, were highly active throughout the gypsy moth egg stage (July–March). A soybean-oil based product has been registered for this use. A 50% concentration of soybean oil is recommended for quarantine purposes, while a 25% concentration should be suitable for homeowners and arborists.

Chromosomal assignment of oil radish resistance to Meloidogyne incognita and M. javanica using a set of disomic rapeseed-radish chromosome addition lines

Nematology ◽  
2014 ◽  
Vol 16 (10) ◽  
pp. 1119-1127
Author(s):  
Shaosong Zhang ◽  
Edgar Schliephake ◽  
Holger Budahn
Keyword(s):  
Meloidogyne Incognita ◽  
Egg Mass ◽  
Addition Line ◽  
Addition Lines ◽  
Root Knot Nematodes ◽  
Egg Masses ◽  
Chromosome Addition ◽  
Radish Root ◽  
Chromosome Addition Lines ◽  
Wide Range

Root-knot nematodes cause severe damage to a great number of crops worldwide. The use of nematicides is restricted due to environmental and toxicological risks and control of the pest by crop rotation is difficult because root-knot nematodes have a very wide range of host plants. To verify the strategy of converting rapeseed from a tolerant host for Meloidogyne incognita and M. javanica to a resistant catch crop, a complete set of nine disomic rapeseed-radish chromosome addition lines (lines A to I) was tested for resistance against these Meloidogyne species. Thirty plants of each addition line and the rapeseed and radish parents as control were infected with 2500 second-stage juveniles per plant. The presence of the alien radish chromosome was confirmed by chromosome-specific microsatellite markers. After cultivation of the inoculated plants for 10 weeks in a climatic chamber the root systems were washed. The egg masses were stained with Cochenille Red and counted. The radish parent A24 was found to be resistant to M. incognita (2.4 egg masses (g root)−1) and M. javanica (0.4 egg masses (g root)−1) compared to 53.3 and 33.1 egg masses (g root)−1 for the susceptible rapeseed parent cv. Madora. The radish chromosome e was shown to be the carrier of radish root-knot nematode resistance with an average number of <1 egg mass (g root)−1 for M. incognita and M. javanica. The disomic addition lines B, C, D, G, H and I and the parental radish line A107 were classified as highly susceptible, whereas the addition lines A and F showed significantly reduced susceptibility for M. incognita but not for M. javanica. To our knowledge this is the first study on resistance effects of individual radish chromosomes in a rapeseed background against these root-knot nematodes.

scholarly journals Spatial Distribution of Lycorma delicatula (Hemiptera: Fulgoridae) Egg Masses on Tree-of-Heaven, Black Walnut, and Siberian Elm in North America

2019 ◽  
Vol 113 (2) ◽  
pp. 1028-1032 ◽  
Author(s):  
Houping Liu ◽  
Richard J Hartlieb
Keyword(s):  
Spatial Distribution ◽  
Tree Height ◽  
Black Walnut ◽  
Egg Mass ◽  
Egg Masses ◽  
North West ◽  
Tree Of Heaven ◽  
Significant Difference ◽  
Cardinal Direction ◽  
Lycorma Delicatula

Abstract The spatial distribution of Lycorma delicatula (White) egg masses on three species of trees were studied in Pennsylvania. Five tree-of-heaven, five black walnut, and one Siberian elm trees were felled in early spring 2019 to sample for egg masses. Each egg mass was marked for its cardinal direction, position in the tree, height above ground, and spread from the bole. A total of 214 egg masses were found on tree-of-heaven and black walnut, with 38.3, 29.4, 22.0, and 10.3% on the north, west, south, and east quadrant, respectively. No significant difference in cardinal direction was found for either species. Equal number of egg masses were found on branches and boles on tree-of-heaven. However, significantly more egg masses were found on branches (96.5%) compared to boles (3.5%) on black walnut. Egg masses were laid at 0.30–12.92 and 0.70–17.00 m above ground, with most on boles/higher branches and middle/lower branches for tree-of-heaven and black walnut, respectively. Significant effect of height above ground was found for black walnut, with more egg masses found at 4–6 m compared to 0–2, 12–14, and 14–16 m. Significant effect of spread from the bole was found for tree-of-heaven, with more egg masses found at 0–2 m compared to 2–4 and 4–6 m. The 24 egg masses on the Siberian elm were mostly found on east quadrant branches 0–2 m above ground and within 2 m from the bole. Variation in tree branching patterns and difference in egg mass distribution of other forest pests were discussed.

DEVELOPMENT AND EVALUATION OF A SAMPLING SCHEME FOR THE GYPSY MOTH EGG PARASITOID OOENCYRTUS KUVANAE (HYMENOPTERA: ENCYRTIDAE)

1981 ◽  
Vol 113 (7) ◽  
pp. 575-584 ◽  
Author(s):  
M. W. Brown ◽  
James L. Rosenberger ◽  
E. Alan Cameron
Keyword(s):  
Gypsy Moth ◽  
Negative Binomial ◽  
Sampling Methods ◽  
Field Evaluation ◽  
Egg Parasitoid ◽  
Sampling Scheme ◽  
Egg Mass ◽  
Egg Masses ◽  
Coefficients Of Variation ◽  
Ooencyrtus Kuvanae

AbstractFour sampling methods for Ooencyrtus kuvanae (Howard) populations were compared for efficiency using coefficients of variation. On this basis, none of the sampling methods was uniformly superior to any other, but a cluster of 0.01 ha subplots was chosen as the best method because of the aggregation of both gypsy moth egg masses and parasitoids. From the estimated population variance per egg mass it was calculated that 150 egg masses should be sampled per plot to provide an error bound of 0.2 parasitoid per egg mass (α = 0.1). An analysis of variance indicated that variation among study areas was the largest source of variation, and that among day, within day, and plot configuration variation were significant. Estimates of parasitoid activity are most reliable during the period between 1300 and 1600 h EST. Activity of parasitoids was reduced on overcast days. In August, the distribution of O. kuvanae approximates that of the negative binomial but with too many individuals in the high frequency classes. In a compromise between cost and accuracy, the sampling scheme selected consists of thirty 0.01 ha subplots per plot sampled between 1300 and 1600 h EST on sunny days. This sampling scheme was found satisfactory using field evaluation.

INFLUENCE OF NATURAL DIETS AND LARVAL DENSITY ON GYPSY MOTH, LYMANTRIA DISPAR (LEPIDOPTERA: ORGYIIDAE), EGG MASS CHARACTERISTICS

1977 ◽  
Vol 109 (10) ◽  
pp. 1313-1318 ◽  
Author(s):  
John L. Capinera ◽  
Pedro Barbosa
Keyword(s):  
Gypsy Moth ◽  
Egg Size ◽  
Larval Density ◽  
Field Studies ◽  
Forest Composition ◽  
Egg Mass ◽  
Natural Diet ◽  
Egg Masses ◽  
Egg Number ◽  
Host Tree Species

AbstractLaboratory and field studies indicate that differences in gypsy moth egg mass characteristics can be related to larval density and natural diet. Egg mass characteristics are valuable indices of population quality as well as future population levels. Laboratory crowding reduced number of eggs/mass but did not affect egg size. Field collected egg masses from various population levels in Massachusetts also varied in egg number/mass, but egg size could not be directly correlated to density. Laboratory rearing of larvae on several natural diets produced differences in both egg number and size. Maple diets produced egg masses with fewer, smaller eggs, as compared with oak diets. Field collected egg masses also varied in mean egg size, according to host tree species. Thus, forest composition may directly affect the quality of gypsy moth populations, as well as numerical levels. Increasing density could affect egg size indirectly, by forcing gypsy moth larvae to feed on unfavorable host foliage.

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