scholarly journals Population Density and Killing Capacity by Predators of Eggs and Larvae of the Diamondback Moth in Nicaragua

2011 ◽  
Vol 40 (2) ◽  
pp. 333-341 ◽  
Author(s):  
Freddy Miranda ◽  
Helena Bylund ◽  
Lina Grönberg ◽  
Linda Larsson ◽  
Christer Björkman
Keyword(s):  
Population Density ◽  
Diamondback Moth ◽  
Eggs And Larvae

scholarly journals Effect of the product of radiational removal of SO2 and NOx from combustion gases on the population of Globodera rostochiensis nematodes (Woll., Behrens 1975)

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 642-644
Author(s):  
G. Kaup ◽  
K. Janowicz ◽  
K. Paruch
Keyword(s):  
Population Density ◽  
Globodera Rostochiensis ◽  
Combustion Gases ◽  
Growing Seasons ◽  
Second Year ◽  
Lower Population ◽  
Eggs And Larvae ◽  
Lower Population Density

The studies were carried out in a greenhouse of the Agricultural University of Szczecin, during two growing seasons. The aim of this study was determine the effect of the product obtained from radiational SO<sub>2</sub> and NO<sub>x</sub> removal from combustion gases on the populations of Globodera rostochiensis nematodes — one of the most common quarantine organisms. The analysis of the effect of the applied product on the population of nematodes demonstrated their varied character of response. In the combination with the product of radiational purification of combustion gases, also significantly lower population density (number of eggs and larvae in 1 g of soil) and lower fecundity of Globodera rostochiensis females were observed compared to the control combination. And in the second year of the experiment, the number of cysts in the combination with the product of SO<sub>2</sub> and NO<sub>x</sub> removal from combustion gases was significantly lower compared to the control, and was less than half of the quantity of the previous year.

scholarly journals Food availability and larval density affect ovarian development in Plutella xylostella (L.) (Lepidoptera: Yponomeutidae)

1999 ◽  
Vol 28 (4) ◽  
pp. 611-616 ◽  
Author(s):  
Marina Castelo Branco ◽  
Alexander G. Gatehouse
Keyword(s):  
Population Density ◽  
Food Availability ◽  
Plutella Xylostella ◽  
Ovarian Development ◽  
Diamondback Moth ◽  
Larval Density ◽  
Leaf Disk ◽  
Plant Age ◽  
Insect Migration ◽  
Petri Dishes

The effect of Diamondback Moth (Plutella xylostella L.) population density and plant age on the rate of ovarian development was investigated. In tests carried out in Petri dishes, the density of larvae/leaf disk affected the rate of ovarian development. A high proportion of moths from larvae reared on leak disks from two or four-month-old spring cabbage at a density of seven or 14 larvae/leaf disk were mature at emergence. But moths reared at the same type of plant at a density of 28 larvae/leaf disk were largely immature at emergence. When the larvae were reared at a density of 30 larvae/plant on two or four-month-old spring cabbage plants, a high proportion of females were mature at emergence. Crowding has an important effect on the rate of ovarian development in Diamondback Moth with possible consequences for the migratory potential of moths, as insect migration generally occurs when the ovaries of the females are immature. The density of moths necessary to increase the proportion of immature females in the field is probably higher than 30 larvae/plant.

scholarly journals Effectiveness of Spinosad against Diamondback Moth (Plutella xylostella L.) Eggs and Larvae on Cabbage under Botswana Conditions

2014 ◽  
Vol 6 ◽  
pp. IJIS.S12531 ◽  
Author(s):  
Mitch M. Legwaila ◽  
David C. Munthali ◽  
Motshwari Obopile ◽  
Baone C. Kwerepe
Keyword(s):  
Plutella Xylostella ◽  
Larval Mortality ◽  
Diamondback Moth ◽  
Rapid Change ◽  
Probit Analysis ◽  
Effective Control ◽  
College Of Agriculture ◽  
Egg Mortality ◽  
Eggs And Larvae

The efficacy of spinosad against the diamondback moth (DBM) on cabbage was studied at Botswana College of Agriculture, Gaborone, Botswana in 2011. Using five concentrations of spinosad: 0.12, 0.36, 0.60, 0.84 and 1.08 g/L, bioassays were conducted against DBM eggs and second instar larvae at 30°C ± 5°C. Each treatment was replicated three times. Probit analysis was used to determine LD50 and LD90 values for the treatments against eggs and larvae. When the treatments were assessed at 72 and 96 hours, LD90 values against larvae were 0.74 and 0.59 g/L, whereas they were 0.35 and 0.32 g/L against eggs. This indicated that spinosad was more effective against eggs than against larvae. The slopes of the probit lines for larvae assessed at 48, 72 and 96 hours after application were 3.519, 3.810 and 3.427, while those against eggs were 1.725, 1.316 and 1.086. This indicates that there was a more rapid change in larval mortality with increase in pesticide dosage than in egg mortality. The study shows that spinosad can achieve effective control of DBM eggs and larvae under Botswana conditions.

scholarly journals Effect of Intercropping White Cabbage with French Marigold (Tagetes Patula Nana) and Pot Marigold (Calendula Officinalis) on Diamondback Moth (Plutella Xylostella L.) Population Density and it's Parasitoid Complex

2010 ◽  
Vol 73 (1) ◽  
pp. 107-117 ◽  
Author(s):  
Beata Jankowska
Keyword(s):  
Population Density ◽  
Plutella Xylostella ◽  
Diamondback Moth ◽  
Abundant Species ◽  
Tagetes Patula ◽  
Calendula Officinalis ◽  
Parasitoid Complex ◽  
White Cabbage ◽  
Pot Marigold ◽  
The Impact

Effect of Intercropping White Cabbage with French Marigold (Tagetes Patula Nana) and Pot Marigold (Calendula Officinalis) on Diamondback Moth (Plutella XylostellaL.) Population Density and it's Parasitoid ComplexThe impact of intercropping white cabbage (‘Bently F1’) with French MarigoldTagetes patula nana‘Kolombina’ and Pot MarigoldCalendula officinalis‘Promyk’ on the occurrence of diamondback moth (DBM) (Plutella xylostellaL.) and its parasitoid complex was estimated in years 2003-2005. The number of DBM larvae and pupae was significantly lower on plots where cabbage was intercropped compared with the control variant (homogenous crop). The combination with Pot Marigold turned out to be the best in this respect. The DBM larvae parasitization level varied from year to year and its percentage oscillated from 65 to 88%. Eight beneficial insect species belonging to families:Ichneumonidae(4 species),Braconidae(2 species),Pteromalidae(1 species) andEulophidae(1 species) emerged from collected DBM pupae.Diadegma fenestralisHolmgr. was the most abundant species among allPlutellaparasitoids every year of observations as it constitued 65% of all of the reared wasps. No significant differences were determined between the level of parasitization in relation to the type of cultivation.

scholarly journals Effect of Population Density on Timing of Oviposition and Brood Size Reduction in the Burying BeetleNicrophorus pustulatusHerschel (Coleoptera: Silphidae)

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Claudia M. Rauter ◽  
Renae L. Rust
Keyword(s):  
Population Density ◽  
High Mortality ◽  
Brood Size ◽  
Physiological Stress ◽  
Reduction Rate ◽  
Brood Reduction ◽  
Burying Beetles ◽  
Physiological Constraints ◽  
Newly Hatched Larvae ◽  
Eggs And Larvae

Burying beetles (Nicrophorusspp.) bury small carcasses to feed their larvae. Carcasses are a limited, high-quality resource and contests over carcasses become more frequent with increasing population density. Successful beetles kill eggs and larvae present on carcass. In response, females should accelerate oviposition, while offspring development should increase to minimize mortality. Both value of a carcass and frequency of contests decrease as larvae develop. If overproduction of offspring is an insurance against high mortality, females should reduce brood size as carcass value declines. Testing our predictions, we reared female burying beetles,Nicrophorus pustulatus, at high and low densities and compared oviposition and brood reduction. High-density females delayed oviposition, suggesting that high population density imposes nutritional and/or physiological stress. Females responded to the physiological constraints and the potentially high mortality rates of eggs and newly hatched larvae by lengthening oviposition period and changing brood reduction rate.

Evaluation of discrete host–parasitoid models for diamondback moth and Diadegma semiclausum field time population density series

2009 ◽  
Vol 220 (15) ◽  
pp. 1735-1744 ◽  
Author(s):  
Henri E.Z. Tonnang ◽  
Lev V. Nedorezov ◽  
John O. Owino ◽  
Horace Ochanda ◽  
Bernhard Löhr
Keyword(s):  
Population Density ◽  
Diamondback Moth ◽  
Diadegma Semiclausum

scholarly journals Efficacy of Bacillus Thuringiensis (var. Kurstaki) against Diamondback Moth (Plutella Xylostella L.) Eggs and Larvae on Cabbage Under Semi-Controlled Greenhouse Conditions

2015 ◽  
Vol 7 ◽  
pp. IJIS.S23637 ◽  
Author(s):  
Mitch M. Legwaila ◽  
David C. Munthali ◽  
Baone C. Kwerepe ◽  
Motshwari Obopile
Keyword(s):  
Bacillus Thuringiensis ◽  
Plutella Xylostella ◽  
Diamondback Moth ◽  
Probit Analysis ◽  
Effective Control ◽  
College Of Agriculture ◽  
Expected Time ◽  
Eggs And Larvae

The efficacy of Bacillus thuringiensis (var. kurstaki) ( Btk) against the diamondback moth (DBM) on cabbage was studied at Botswana College of Agriculture, Gaborone, Botswana. Using five concentrations of Btk: 2, 4, 6, 8, and 10 g/L, bioassays were conducted against DBM eggs and second instar larvae at 30°C ± 5°C. Each treatment was replicated three times. Probit analysis was used to determine the LD50 and LD90 values for the treatments against eggs and larvae. When the treatments were assessed at 72, 96, 120, and 144 hours, LD90 values against larvae were 11.02, 10.22, 5.92, and 4.01 g/L, whereas they were 7.71, 6.94, and 6.24 g/L against eggs when assessed 48, 72, and 96 hours after the expected time of hatching. This indicated that Btk was effective against both eggs and larvae when exposed for long periods. The slopes of the probit lines for larvae assessed at 24, 48, 72, 96, 120, and 144 hours after application were 0.250, 1.064, 0.910, 0.383, 0.453, and 0.414, while those against eggs were 1.153, 1.246, and 0.933 when assessed 48, 72, and 96 hours after the expected time of hatching. This indicates a smaller change in mortality with increase in pesticide dosage for both eggs and larvae. Btk treatments achieved 85.7%–94.6% reduction in DBM damage on cabbage. Therefore, Btk can be used to achieve effective control of DBM eggs and larvae and reduce damage on cabbage under greenhouse conditions.

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