scholarly journals Techniques for detecting Actinidia resistance to leafrollers

2006 ◽  
Vol 59 ◽  
pp. 51-56
Author(s):  
C.E. McKenna ◽  
S.J. Dobson ◽  
P.G. Connolly
Keyword(s):  
Plant Material ◽  
Larval Survival ◽  
Artificial Diets ◽  
Leaf Discs ◽  
Relative Susceptibility ◽  
Ctenopseustis Obliquana

Hayward and Hort16A kiwifruit are susceptible to attack by the brownheaded leafroller (BHLR) Ctenopseustis obliquana but the incidence and severity of damage to Hayward can be twice that of Hort16A Three bioassay techniques were tested for their ability to detect differences in the relative susceptibility of the two kiwifruit cultivars to BHLR larvae No differences were detected when larvae were reared on artificial diets containing Hayward or Hort16A plant material Significantly more larvae survived when reared on Hayward versus Hort16A leaf discs Caging larvae onto leaves and fruit resulted in significantly more damage to Hayward compared with Hort16A Measuring larval survival after 21 days on leaf discs or the incidence and severity of damage caused by larvae caged on leaves or fruit are both potential techniques for screening Actinidia plant material for resistance to leafrollers

Artificial diets in sea urchin culture: effects of dietary protein level and other additives on egg quality, larval morphometries, and larval survival in the green sea urchin, Strongylocentrotus droebachiensis

1995 ◽  
Vol 73 (11) ◽  
pp. 2080-2090 ◽  
Author(s):  
Marja de Jong-Westman ◽  
Pei-Yuan Qian ◽  
Beryl E. March ◽  
Thomas H. Carefoot
Keyword(s):  
Sea Urchin ◽  
Energy Content ◽  
High Protein Diet ◽  
Larval Survival ◽  
Strongylocentrotus Droebachiensis ◽  
High Protein ◽  
Protein Diet ◽  
Artificial Diets ◽  
Green Sea Urchin ◽  
Β Carotene

The effect of artificial diets on the size and energy content of eggs and morphometry, survival, and metamorphic success of larvae was investigated in the green sea urchin, Strongylocentrotus droebachiensis, from the standpoint of developing a good broodstock diet for culturists. Groups of sea urchins were fed eight diets over a period of 9 months, then five of these dietary groups were selected for detailed larval-growth studies. The artificial diets differed in protein content and in various additives including mannitol, algin, cholesterol, and β-carotene; a diet of air-dried kelp was also included. Egg-energy content was highest on a high-protein diet with cholesterol and β-carotene additives, and the largest eggs so far recorded for the species (2.39 mm3 × 10−3) were produced on a high-protein diet with cholesterol additive. Larval survival to metamorphosis was >92% for all diets save for kelp (<5%). Kelp-fed adults also produced poorly metamorphosing larvae (<2%), suggesting that air-drying causes chemical changes in the kelp that are ultimately detrimental to larval health. Larval developmental rates were fastest on the high-protein β-carotene formulation. Larvae from this diet group also had the longest arms relative to body length, largest rudiment diameter, largest absolute and relative ciliated-band length (for efficient feeding), and had a high percentage of metamorphosis. These data suggest that a high-protein β-carotene diet will be useful for conditioning broodstock by prospective sea urchin culturists.

scholarly journals Adaptation of artificial diets for Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) at laboratory rearing

2018 ◽  
Author(s):  
Caio C. Truzi ◽  
Hurian G. Holzhausen ◽  
José A. Chamessanga ◽  
Valéria L. Laurentis ◽  
Natalia F. Vieira ◽  
...  
Keyword(s):  
Protein Content ◽  
Helicoverpa Armigera ◽  
Metabolic Cost ◽  
Larval Survival ◽  
Reproductive Rate ◽  
Artificial Diets ◽  
Net Reproductive Rate ◽  
Protein Levels ◽  
Helicoverpa Armígera ◽  
Biological Aspects

ABSTRACTHelicoverpa armigera is an important pest of crops worldwide, and several studies have focused on the development of artificial diets for this species. However, studies evaluating the insect´s performance at nutritionally different diets are scarce. Larval development is dependent on the ratio of protein and carbohydrates. The aim of this study was to evaluate the biology and to compare the consumption and use of food of H. armigera larvae on diets with different protein levels. The nutritional index, the relative consumption rate, the relative metabolic rate, the relative growth rate, and the apparent digestibility were higher in the diet with added protein. On the other hand, the conversion efficiency of digested food was lower, resulting in a higher metabolic cost. In terms of biological aspects, larval survival was higher for the diet with average protein content and lower for the diet with a high protein level. The pupal period was longer for the diet with a higher protein content, while pupal survival was lower. Among the evaluated diets, the diet with an average protein content resulted in a higher net reproductive rate, a shorter time for the population to double in number, and the highest rates of population growth. The results suggest that lower or higher protein contents in the diets of H. armigera negatively affect the biological aspects of this species.

scholarly journals Comparison of Six Artificial Diets for Western Corn Rootworm Bioassays and Rearing

2018 ◽  
Vol 111 (6) ◽  
pp. 2727-2733 ◽  
Author(s):  
Lisa N Meihls ◽  
Man P Huynh ◽  
Dalton C Ludwick ◽  
Thomas A Coudron ◽  
B Wade French ◽  
...  
Keyword(s):  
Artificial Diet ◽  
Extended Period ◽  
Dry Weight ◽  
Diabrotica Virgifera Virgifera ◽  
Larval Survival ◽  
Western Corn Rootworm ◽  
Fourth Instar ◽  
Corn Rootworm ◽  
Artificial Diets ◽  
Testing Susceptibility

Abstract The western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is considered the most important maize (Zea mays L.) pest in the U.S. Corn Belt. Bioassays testing susceptibility to Bacillus thuringiensis Berliner (Bt) and other toxins of corn rootworm larvae often rely on artificial diet formulations. Successful bioassays on artificial diet for corn rootworm have sometimes been challenging because of microbial contamination. Toward the long-term goal of developing a universal artificial diet for western corn rootworm larvae, we compared larval survival, dry weight, and percentage of molt in 10-d bioassays from six current diets of which we were aware. In addition, as part of longer term rearing efforts, we recorded molting over an extended period of development (60 d). Six different artificial diets, including four proprietary industry diets (A, B, C, and D), the first published artificial diet for western corn rootworm (Pleau), and a new diet (WCRMO-1) were evaluated. Western corn rootworm larval survival was above 90% and contamination was 0% on all diets for 10 d. Diet D resulted in the greatest dry weight and percentage molting when compared with the other diets. Although fourth-instar western corn rootworm larvae have not been documented previously (only three instars have been previously documented), as many as 10% of the larvae from Diet B molted into a fourth instar prior to pupating. Overall, significant differences were found among artificial diets currently used to screen western corn rootworm. In order for data from differing toxins to be compared, a single, reliable and high-quality western corn rootworm artificial diet should eventually be chosen by industry, academia, and the public as a standard for bioassays.

REARING OF TRICHOSIROCALUS HORRIDUS (COLEOPTERA: CURCULIONIDAE) LARVAE IN ARTIFICIAL DIETS

1987 ◽  
Vol 22 (4) ◽  
pp. 330-335 ◽  
Author(s):  
Thomas J. McAvoy ◽  
Loke-Tuck Kok
Keyword(s):  
Larval Development ◽  
Larval Growth ◽  
Casein Hydrolysate ◽  
Larval Survival ◽  
Natural Host ◽  
The Other ◽  
Vitamin Supplement ◽  
Artificial Diets

Diet components of an initially acceptable diet for larvae of Trichosirocalus horridus (Panzer), an introduced weevil for thistle control, Carduus thoermeri Weinmann and C. acanthoides L., were systematically varied to determine if the yield of adult weevils could be improved. A total of 56 new diets were prepared and tested. Survival to the late third instar was slightly improved up to 39%, while larval development improved with additions of Vandersant Vitamin Supplement (8 g per 425 ml batch of diet), lyophilized thistle roots, ergosterol, or by transferring larvae to identical fresh diets after 4 weeks. However, larval survival decreased when excessive casein hydrolysate or 7-dehydrocholesterol was used. Sucrose did not improve larval growth. Of the six new diets that supported complete larval development, one diet yielded two adults, while the other five yielded one adult each. Only one of the diet-reared females oviposited eggs, and longevity of diet-reared adults was shorter than adults reared from its natural host, musk thistle.

scholarly journals Larval feeding behaviour and toxicity of Bacillus thuringiensis against Ctenopseustis obliquana on avocados

2001 ◽  
Vol 54 ◽  
pp. 21-26
Author(s):  
P. Stevens ◽  
P. Jamieson ◽  
L.E. Jamieson ◽  
M. Knights
Keyword(s):  
Bacillus Thuringiensis ◽  
Feeding Behaviour ◽  
Tree Canopy ◽  
Short Exposure ◽  
Larval Feeding ◽  
Leaf Discs ◽  
First Instar ◽  
Outer Perimeter ◽  
Ctenopseustis Obliquana ◽  
Third Instar Larvae

Ctenopseustis obliquana is a serious pest of avocado in New Zealand Laboratory experiments to gain a greater understanding of the interaction between larval feeding behaviour and environmental degradation of Bacillus thuringiensis (Bt) residues were carried out Larval C obliquana were found to feed equally during light and dark periods and the application of Bt sprays in the evening did not consistently result in higher mortality than sprays applied in the morning First instar larvae were more susceptible to Bt sprays than third instar larvae However when first instar larvae were provided with leaf discs that had been sprayed with Bt seven days previously mortality was equivalent to that of larvae feeding on unsprayed leaves Mortality of first and third instar larvae provided with Bttreated leaf discs collected from within the shade of the avocado tree canopy (zero and one day after spraying) was significantly greater than that of larvae provided with Bttreated leaf discs collected from the outer perimeter of the canopy Results indicated that even very short exposure to sunlight (ie 3060 minutes) was sufficient to cause a significant reduction in the toxicity of Btsprayed leaves to C obliquana larvae

BIOEFFICACY OF PLANT EXTRACTS AGAINST MUSTARD APHID AND THEIR NATURAL ENEMIES

2019 ◽  
Vol 25 (1) ◽  
Author(s):  
NARENDRA SINGH ◽  
N. S. BHADAURIA ◽  
PRADYUMN SINGH
Keyword(s):  
Plant Extracts ◽  
Natural Enemies ◽  
Untreated Control ◽  
Plant Material ◽  
Aphid Population ◽  
College Of Agriculture ◽  
Mustard Aphid ◽  
Plant Materials

The Bio-efficacy of eleven plant extracts namely viz.Neem Kernel; Rhizome of Ginger; Leaves of Datura, Gajarghas, Harsingar, Oak and Latjeera; Bulb of Garlic and Onion; Flowers of Chrysenthemum and Fruits of Chilli in the concentration of 5 percent and imidacloprid @ 40 g ai/ha was tested against mustard aphid, Lipaphiserysimi and their effect on D. rapae and Coccinellid beetle were tested in the Department of Entomology, College of Agriculture, Gwalior (M.P.). All the tested plant materials and imidacloprid @ 40 g ai/ha were effective significanty in reducing the aphid population over control.The aphid population in treated plots ranged from 7.2 to 40.0 as against 85.4 aphid/twig in untreated control. Among the plant material, three sprays of Neem Kernel were found most effective followed by three sprays of chilli fruits.All the plant extracts were found significantly safer to D. rapae and coccinellid bettle in comparision to insecticide (imidacloprid).

The box-balance model: a new tool to assess fish larval survival, applied to field data on two small pelagic fish

2020 ◽  
Vol 650 ◽  
pp. 289-308 ◽  
Author(s):  
V Raya ◽  
J Salat ◽  
A Sabatés
Keyword(s):  
Field Data ◽  
Fish Larvae ◽  
Larval Growth ◽  
Warming Trend ◽  
Mortality Rates ◽  
Larval Survival ◽  
Pelagic Fish ◽  
Balance Model ◽  
Small Pelagic Fish ◽  
Mesoscale Structures

This work develops a new method, the box-balance model (BBM), to assess the role of hydrodynamic structures in the survival of fish larvae. The BBM was applied in the northwest Mediterranean to field data, on 2 small pelagic fish species whose larvae coexist in summer: Engraulis encrasicolus, a dominant species, and Sardinella aurita, which is expanding northwards in relation to sea warming. The BBM allows one to quantify the contribution of circulation, with significant mesoscale activity, to the survival of fish larvae, clearly separating the effect of transport from biological factors. It is based on comparing the larval abundances at age found in local target areas, associated with the mesoscale structures (boxes), to those predicted by the overall mortality rate of the population in the region. The application of the BBM reveals that dispersion/retention by hydrodynamic structures favours the survival of E. encrasicolus larvae. In addition, since larval growth and mortality rates of the species are required parameters for application of the BBM, we present their estimates for S. aurita in the region for the first time. Although growth and mortality rates found for S. aurita are both higher than for E. encrasicolus, their combined effect confers a lower survival to S. aurita larvae. Thus, although the warming trend in the region would contribute to the expansion of the fast-growing species S. aurita, we can confirm that E. encrasicolus is well established, with a better adapted survival strategy.

Climate-associated trends and variability in ichthyoplankton phenology from the longest continuous larval fish time series on the east coast of the United States

2020 ◽  
Vol 650 ◽  
pp. 269-287
Author(s):  
WC Thaxton ◽  
JC Taylor ◽  
RG Asch
Keyword(s):  
United States ◽  
Environmental Variability ◽  
Larval Fish ◽  
Interspecific Interactions ◽  
River Estuary ◽  
Atlantic Multidecadal Oscillation ◽  
The United States ◽  
Larval Survival ◽  
Ecological Communities ◽  
Northerly Wind

As the effects of climate change become more pronounced, variation in the direction and magnitude of shifts in species occurrence in space and time may disrupt interspecific interactions in ecological communities. In this study, we examined how the fall and winter ichthyoplankton community in the Newport River Estuary located inshore of Pamlico Sound in the southeastern United States has responded to environmental variability over the last 27 yr. We relate the timing of estuarine ingress of 10 larval fish species to changes in sea surface temperature (SST), the Atlantic Multidecadal Oscillation, the North Atlantic Oscillation, wind strength and phenology, and tidal height. We also examined whether any species exhibited trends in ingress phenology over the last 3 decades. Species varied in the magnitude of their responses to all of the environmental variables studied, but most shared a common direction of change. SST and northerly wind strength had the largest impact on estuarine ingress phenology, with most species ingressing earlier during warm years and delaying ingress during years with strong northerly winds. As SST warms in the coming decades, the average date of ingress of some species (Atlantic croaker Micropogonias undulatus, summer flounder Paralichthys dentatus, pinfish Lagodon rhomboides) is projected to advance on the order of weeks to months, assuming temperatures do not exceed a threshold at which species can no longer respond through changes in phenology. These shifts in ingress could affect larval survival and growth since environmental conditions in the estuarine and pelagic nursery habitats of fishes also vary seasonally.

EVALUATION OF CLOVERS ON SANDY COASTAL SOIL

1977 ◽  
pp. 130-138 ◽  
Author(s):  
W.M. Williams ◽  
L.B. Anderson ◽  
B.M. Cooper
Keyword(s):  
New Zealand ◽  
Drought Stress ◽  
Sandy Soil ◽  
White Clover ◽  
Plant Material ◽  
Red Clover ◽  
Early Spring ◽  
Commercial Cultivars ◽  
Mediterranean Origin ◽  
Winter Annual

In evaluations of clover performances on summer-dry Himatangi sandy soil, it was found that none could match lucerne over summer. Emphasis was therefore placed on production in autumn-winter- early spring when lucerne growth was slow. Evaluations of some winter annual clover species suggested that Trifolium spumosum, T. pallidum, T. resupinatum, and T. vesiculosum would justify further investigation, along with T. subterraneum which is already used in pastures on this soil type. Among the perennial clover species, Kenya white clover (7'. semipilosum) showed outstanding recovery from drought and was the only species to produce significantly in autumn. However, it failed to grow in winter-early spring. Within red clover, materials of New Zealand x Moroccan origin substantially outproduced the commercial cultivars. Within white clover, material from Israel, Italy and Lebanon, as well as progeny of a selected New Zealand plant, showed more rapid recovery from drought stress and subsequently better winter growth than New Zealand commercial material ('Grasslands Huia'). The wider use of plant material of Mediterranean origin and of plants collected in New Zealand dryland pastures is advocated in development of clover cultivars for New Zealand dryland situations.

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