Factors affecting the phenology of the first brood of the sugar-cane froghopper Aeneolamia varia saccharina (Dist.) (Homoptera, Cercopidae) in Trinidad

1975 ◽  
Vol 65 (3) ◽  
pp. 359-372 ◽  
Author(s):  
A. B. S. King
Keyword(s):  
Adult Emergence ◽  
Dry Season ◽  
Soil Conditions ◽  
Factors Affecting ◽  
Expected Time ◽  
Short Period ◽  
Incubation Periods ◽  
Close Relationship ◽  
Dry Soil ◽  
Predictive Relationship

AbstractThe size and occurrence of the first brood of adults of Aeneolamia varia saccharina (Dist.) are examined in relation to the pattern of egg eclosion and rainfall. The proportion of eggs hatching within a month of oviposition in the laboratory (short-period eggs) decreased from over 90% in August to less than 20% in January, but the incubation periods of the remaining, long-period eggs were longest in those laid during October and November. The overall hatching distributions tended to be bimodal with most eggs hatching during the early months of the year under moist conditions at 26°C. Dry soil conditions delay eclosion, and eggs obtained from fields during the dry season and then incubated under moist conditions tended to hatch at the normally expected time of the first rains in May. The numbers of eggs expected to produce the first brood, computed from laboratory hatching data and estimates of the numbers and fecundities of froghoppers during the second, third and fourth broods, were less than the actual numbers sampled just before the first rains. There was a close relationship between the first rainfall of over one inch within 48 h and adult emergence 27 and 34 days later, and 85% of field egg populations in May had hatched and/or died by the week after the first rains. However some variation in the date of their occurrence accounted for non-synchrony of first broods over the region. The numbers of diapause eggs in fields sampled during the dry season failed to give a good predictive relationship with first brood adult populations, probably because of density dependent mortality of eggs or hatchling nymphs.

FACTORS AFFECTING SUBSEQUENT GERMINATION OF CEREAL SEEDS SOWN IN SOILS OF SUBGERMINATION MOISTURE CONTENT

1960 ◽  
Vol 38 (3) ◽  
pp. 287-306 ◽  
Author(s):  
H. A. H. Wallace
Keyword(s):  
Moisture Content ◽  
Seed Coat ◽  
Soil Conditions ◽  
Moist Soil ◽  
Factors Affecting ◽  
Storage Fungi ◽  
Untreated Check ◽  
Dry Soil ◽  
Germinating Seeds ◽  
Standard Weight

Seeds of wheat sown in soils of subgermination moisture content sometimes decay and die. The critical moisture content at which maximum seed decay occurs is at a level approximately equal to one-half the difference between air-dry soil and soil moist enough for seed to germinate. The relationship apparently holds irrespective of soil type, even though the actual moisture percentage of different soil types at the critical level is quite distinct. “Dry” soil as used in these studies refers to air-dry soil with 8% moisture added. The subsequent germination of wheat was reduced after 3 days' incubation in “dry” soil at 30 °C, and 14–20 days at 5 °C. Germinability was reduced in strongly saline soil. Different samples of wheat varied greatly in germinability after incubation in “dry” soil. Sterilizing the “dry” soil did not change its effect on germination of various seed lots.Much of the variation in loss of germinability was correlated with thresher injuries to the seed coat. Wheat, rye, and hull-less varieties of oats and barley, especially with seeds of more than standard weight per bushel, are susceptible to thresher injury. Growth cracks, sprouting, and frost injury all affect germination adversely. Cereal seeds with hulls, or with high moisture content, or below standard weight, or of small size, and wheat without projecting embryos, are less susceptible to thresher injury, and to consequent reduction of germinability.The “field” fungi Alternaria sp. and Helminthosporium spp. grew out of cereal seeds plated on potato-sucrose agar or moistened filter paper and from germinated seeds grown in “moist” soil. After incubation in “dry” soil germinating seeds gave rise to Alternaria, but not to Helminthosporium spp. The non-germinating seeds from “dry” soil were infected by “storage” fungi, e.g. Penicillium, Aspergillus, Rhizopus, and Mucor. The “storage” fungi do not usually infect cereal seeds sown in “moist” soil, but in “dry” soil both sound and injured seed can be infected. The infection of sound seed is slow, permitting the seed to germinate, but injured seed is infected rapidly and does not germinate. The “storage” fungi invade seeds already infected by “field” fungi and inhibit the growth of the latter.All samples of treated and untreated wheat seed sown in “moist” soil gave good germination. After incubation in “dry” soil the germination of treated seed was fair to good, and of untreated seed was poor to good. Treatment with formalin before incubation in “dry” soil doubled the germination; treatment with Ceresan M, Half-ounce Leytosan, and a water soak trebled germination compared with the untreated check. However, the best treatment in “dry” soil gave 31% less germination than the untreated check sown in “moist” soil. Under “dry” soil conditions a sound seed coat appears to provide better protection against seed-decaying organisms than any seed treatment tested.

FACTORS AFFECTING ADULT EMERGENCE AND MATING BEHAVIOR OF THE EASTERN SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

1975 ◽  
Vol 107 (9) ◽  
pp. 967-977 ◽  
Author(s):  
C. J. Sanders
Keyword(s):  
Field Experiments ◽  
Choristoneura Fumiferana ◽  
Adult Emergence ◽  
Spruce Budworm ◽  
Field Conditions ◽  
Continuous Illumination ◽  
Degree Days ◽  
Factors Affecting ◽  
Eastern Spruce Budworm ◽  
Duration Of Copulation

AbstractLaboratory and field experiments indicate that the female spruce budworm (Choristoneura fumiferana (Clem.)) pupal stadium requires approximately 122C degree-days above a threshold of 7.2 °C (45°F), the male 124. Emergence time on any given day depends on temperature but is independent of photoperiod. Under field conditions male and female budworm mate only once per 24-h period. In the laboratory under continuous illumination females mate repeatedly and males readily mate a second time within a few hours, but the duration of the second copulation is abnormally long. The probability of multiple matings under field conditions is reduced by the restricted period of sexual activity coupled with the duration of copulation and the lower competitiveness of mated insects. Antennae are essential to the male for successful copulation.

Spoilage of Fish in the Vessels at Sea: 2. Treatment on the Deck and in the Hold

1956 ◽  
Vol 13 (1) ◽  
pp. 21-39 ◽  
Author(s):  
C. H. Castell ◽  
W. A. MacCallum ◽  
H. E. Power
Keyword(s):  
Storage Period ◽  
Factors Affecting ◽  
Short Period ◽  
Warm Summer ◽  
Subsequent Storage ◽  
Initial Contamination

A study has been made of some of the factors affecting the spoilage rate of fish in the trawlers at sea. It was found that two conditions were major causes of accelerated spoilage: (1) Treatments that resulted in very heavy initial contamination such as storing the fish directly against the slimy wooden pen boards, and (2) Treatments that resulted in a rise in the temperature of the fish. This latter may be a larger increase in temperature for a short period, such as exposure of the fish on the deck during warm summer weather, or a smaller increase over a longer period, such as results from inadequate or inefficient icing.Other types of carelessness and unsanitary conditions did not have any significant effect on the fish until at least 6 or 7 days, as long as they were well iced during the subsequent storage period in the hold.

scholarly journals White Root Rot of Raspberries

1951 ◽  
Vol 4 (3) ◽  
pp. 211
Author(s):  
GC Wade
Keyword(s):  
Soil Moisture ◽  
Root Rot ◽  
Soil Moisture Content ◽  
Soil Conditions ◽  
Causal Organism ◽  
White Root Rot ◽  
High Soil Moisture ◽  
High Soil ◽  
Soil Temperatures ◽  
Dry Soil

The disease known as white root rot affects raspberries, and to a less extent loganberries, in Victoria. The causal organism is a white, sterile fungus that has not been identified. The disease is favoured by dry soil conditions and high soil temperatures. It spreads externally to the host by means of undifferentiated rhizomorphs; and requires a food base for the establishment of infection. The spread of rhizomorphs through the soil is hindered by high soil moisture content and consequent poor aeration of the soil.

Factors Affecting Gelation of Lidocaine Hydrochloride-Loaded Polyelectrolyte Complex Thermosensitivity Gel for Dry Socket Treatment

2021 ◽  
Vol 901 ◽  
pp. 111-116
Author(s):  
Nuttawut Supachawaroj ◽  
Sucharat Limsitthichaikoon
Keyword(s):  
Polyelectrolyte Complex ◽  
Gelation Time ◽  
Lidocaine Hydrochloride ◽  
Gelation Temperature ◽  
High Concentration ◽  
Preparation Methods ◽  
Factors Affecting ◽  
Dry Socket ◽  
Short Period ◽  
Gel Preparation

Dry socket disease, a pocket wound caused by the tooth extraction that resulted in severe acute pain which requires a topical analgesic with rapidly pain reduction and suppress the pain until the wound healed. This study aimed to investigate factors affecting gelation temperature and gelation time of lidocaine hydrochloride (LH)-loaded polyelectrolyte complex (PEC) thermosensitivity gel for treating dry socket wound. The first factor was investigated the effects of the ratio of three different types of polymers as chitosan (CS), hyaluronic acid (HA) and poloxamer407 (P407) on the phase transition caused by temperature. The second factor was examined the effects of gel preparation methods. The results showed that increasing concentration of the cationic polymer as CS induced the separation of the solution to gel (sol-to-gel) system due to the charge of CS and the charge of PEC. The ratio of HA:P407 affected the gel forming which high concentration of P407 reduced the gelation temperature while low concentration of HA disturbed the sol-to-gel state causing coagulation. The viscosity, spreadability, and swelling were significantly increased due to the concomitant increased in each polymer, HA and P407. The particle of the formulation observed under microscope was found to be less than 1 µm. Phase inversion from sol-to-gel was found after a min at 23°C. Since gelation temperature of the purposed formula is supposed to form gel below 37°C within a short period of injection. The results of the study indicate the suitable sol-to-gel forming in the appropriate temperature and time which should be used for further investigation in the efficacy and safety.

scholarly journals The nylon bag technique in the determination of ruminal feed protein degradation

1983 ◽  
Vol 55 (1) ◽  
pp. 1-78 ◽  
Author(s):  
Jouko Setälä
Keyword(s):  
Particulate Matter ◽  
Pore Size ◽  
Control Sample ◽  
Sample Treatment ◽  
Sample Weight ◽  
Factors Affecting ◽  
Experimental Animals ◽  
Incubation Periods ◽  
Feed Protein

The investigation included experiments in which factors affecting the reliability of the nylon bag method were studied. The possibility of applying the feed protein degradabilities to practical feeding conditions was also examined. In the experiments concerning reliability, such factors as bag porosity, sample weight, sample treatment, washing procedure, diets, and differences between animals and incubation days were studied. The feed protein degradabilities were also determined by using as incubation periods the ruminal retention times for particulate matter of different feeds, evaluated as a function of DM intake/100 kg liveweight in different diets. A nylon bag, with a pore size of 40 µm and internal dimensions of 6 X 12 cm was selected for the degradability determinations. The sample weight used in incubations was 57 —60  mg DM/cm2. In the determination of feed protein degradability, when sheep are used as experimental animals, it is recommended that for routine determinations only one animal be used, analyzing the contents of two bags for each incubation period during two successive days. A control sample of which degradability is determined in advance in many sheep, should be used in all incubations in order to control the digestive processes in the rumen of the experimental sheep. The actual degradabilities analyzed by the bag method are applicable in practise, if they are determined using animals at similar feeding levels and on diets similar to those prevailing under the conditions in which the degradabilities are going to be used.

Absorption of 2,4-D, Dicamba, and Glyphosate by Excised Honeyvine Milkweed (Cynanchum Laeve) Leaves

Weed Science ◽  
1983 ◽  
Vol 31 (2) ◽  
pp. 271-274 ◽  
Author(s):  
John K. Soteres ◽  
Don S. Murray ◽  
Eddie Basler
Keyword(s):  
Surface Tension ◽  
Soil Conditions ◽  
Leaf Position ◽  
Drying Time ◽  
Leaf Surfaces ◽  
Anisic Acid ◽  
Dry Soil ◽  
The Difference ◽  
Dichlorophenoxy Acetic Acid ◽  
Reduced Surface

Absorption of 2,4-D [(2,4-dichlorophenoxy) acetic acid], dicamba [3,6-dichloro-o-anisic acid], and the isopropylamine salt of glyphosate [N-(phosphonomethyl) glycine] by excised honeyvine milkweed [Cynanchum laeve(Michx.) Pers.] leaves was determined. Experimental variables included leaf position (terminal vs. basal), a surfactant, 4-isopropenyl-1-methylcyclohexane plus unspecified emulsifiers (SA-77), and leaf collection dates. Absorption of the three herbicides by terminal and basal leaves was increased by the addition of the surfactant. However, the surfactant increased absorption into basal leaves more than into terminal leaves. The surfactant reduced surface tension and increased drying time of water droplets on adaxial leaf surfaces by 50%. The pH of the herbicide solutions was reduced from about 5.8 to about 3.9 by SA-77. Absorption of all three herbicides was greater into terminal than into basal leaves when the surfactant was not present, but the difference disappeared when the surfactant was added. Generally, no differences were observed in the absorption of 2,4-D and dicamba. Glyphosate absorption was greater in terminal leaves collected after a period of adequate moisture than after a period of dry soil conditions.

Oviposition Preference and Larval Performance of Drosophila suzukii (Diptera: Drosophilidae), Spotted-Wing Drosophila: Effects of Fruit Identity and Composition

2019 ◽  
Vol 48 (4) ◽  
pp. 867-881 ◽  
Author(s):  
Laure Olazcuaga ◽  
Nicolas O Rode ◽  
Julien Foucaud ◽  
Benoit Facon ◽  
Virginie Ravigné ◽  
...  
Keyword(s):  
Emerging Adults ◽  
Oviposition Behavior ◽  
Oviposition Preference ◽  
Adult Emergence ◽  
Spotted Wing Drosophila ◽  
Larval Performance ◽  
Drosophila Suzukii ◽  
Management Tools ◽  
Factors Affecting ◽  
And Performance

Abstract A better understanding of the factors affecting host plant use by spotted-wing drosophila (Drosophila suzukii) could aid in the development of efficient management tools and practices to control this pest. Here, proxies of both preference (maternal oviposition behavior) and performance (adult emergence) were evaluated for 12 different fruits in the form of purees. The effect of the chemical composition of the fruits on preference and performance traits was then estimated. We synthesized the literature to interpret our findings in the light of previous studies that measured oviposition preference and larval performance of D. suzukii. We show that fruit identity influences different parts of the life cycle, including oviposition preference under both choice and no-choice conditions, emergence rate, development time, and number of emerging adults. Blackcurrant was always among the most preferred fruit we used, while grape and tomato were the least preferred fruits. Larvae performed better in cranberry, raspberry, strawberry, and cherry than in the other fruits tested. We found that fruit chemical compounds can explain part of the effect of fruit on D. suzukii traits. In particular, oviposition preference under choice conditions was strongly influenced by fruit phosphorus content. In general, the consensus across studies is that raspberry, blackberry, and strawberry are among the best hosts while blackcurrant, grape and rose hips are poor hosts. Our results generally confirm this view but also suggest that oviposition preferences do not necessarily match larval performances. We discuss opportunities to use our results to develop new approaches for pest management.

scholarly journals After-effect of long-term soil management on soil respiration and otherqualitative parameters under prolonged dry soil conditions

2015 ◽  
Vol 39 ◽  
pp. 633-651 ◽  
Author(s):  
Dalia FEIZIENE ◽  
Dalia JANUSAUSKAITE ◽  
Virginijus FEIZA ◽  
Agne PUTRAMENTAITE ◽  
Ausra SINKEVICIENE ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Soil Management ◽  
Soil Conditions ◽  
After Effect ◽  
Dry Soil

scholarly journals Earthworms are little affected by reduced soil tillage methods in vineyards

2017 ◽  
Vol 63 (No. 6) ◽  
pp. 257-263 ◽  
Author(s):  
Faber Florian ◽  
Wachter Elisabeth ◽  
Zaller Johann G
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Soil Tillage ◽  
Soil Conditions ◽  
Reduced Tillage ◽  
No Tillage ◽  
Dry Soil ◽  
The Impact ◽  
Tillage Methods ◽  
Erosion Prevention

Inter-rows in vineyards are commonly tilled in order to control weeds and/or to conserve water. While impacts of tillage on earthworms are well studied in arable systems, very little is known from vineyards. In an experimental vineyard, the impact of four reduced tillage methods on earthworms was examined: rotary hoeing, rotary harrowing, grubbing and no tillage. According to an erosion prevention programme, tillage was applied every other inter-row only while alternating rows retained vegetated. Earthworms were extracted from the treated inter-rows 10, 36, 162 and 188 days after tillage. Across dates, tillage methods had no effect on overall earthworm densities or biomass. Considering each sampling date separately, earthworm densities were affected only at day 36 after tillage leading to lower densities under rotary hoeing (150.7 ± 42.5 worms/m<sup>2</sup>) and no tillage (117.3 ± 24.8 worms/m<sup>2</sup>) than under rotary harrowing (340.0 ± 87.4 worms/m<sup>2</sup>) and grubbing (242.7 ± 43.9 worms/m<sup>2</sup>). Time since tillage significantly increased earthworm densities or biomass, and affected soil moisture and temperature. Across sampling dates, earthworm densities correlated positively with soil moisture and negatively with soil temperature; individual earthworm mass increased with increasing time since tillage. It was concluded that reduced tillage in vineyards has little impact on earthworms when applied in spring under dry soil conditions.

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