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1.
    
1. Ecotypes may arise following allopatric separation from source populations. The simultaneous transfer of an exotic plant to a novel environment, along with its stenophagous herbivore, may complicate more traditional patterns of divergence from the plant and insect source populations. 2. The present study evaluated herbivory effects by two Cyrtobagous salviniae ecotypes on two species of Salvinia: the larger S. molesta and the smaller S. minima. Evaluations were based on relative growth rates, biomass production, coverage, and nutrient cycling in a series of complementary and comparative laboratory and outdoor tank experiments. 3. In general, the experiment results indicated that the smaller Florida ecotype of C. salviniae impacted both Salvinia species more than the larger Brazil ecotype. Herbivory, especially by the Florida ecotype, also improved water quality and accelerated nutrient cycling by increasing the rates of litterfall from the standing crops of salvinia. 4. The smaller size of the Florida ecotype may be adaptive by allowing maximal exploitation of host plants via internal larval feeding, which presumably reduces predation risk while increasing damage to the plant. These findings provide support for relying on the suppressive effects of the Florida ecotype in Florida, rather than introducing the Brazil ecotype to counter new infestations of S. molesta.  相似文献   
2.
In a sandy loam under glass, potato cyst-nematode, Globodera pallida, was controlled in soil to 20 cm deep, and tomato yields were greatly increased by sheet steaming for 4 h, by 977 kg methyl bromide ha-1 or by 448 kg Telone (1,3-dichloropropene mixture or Di-Trapex CP (20% methyl isothiocyanate: 15% chloropicrin:65% dichloropropene-dichloropropane mixture) ha-1 followed by 441 kg dazomet or 11.2 kg oxamyl ha-1. Sheet steaming, unlike the other treatments, had relatively little effect on the nematode in soil 20 to 40 cm deep. Until the apices of the plants were cut off production of fruit was curvilinear against time in all treated soil but linear against time in untreated soil.  相似文献   
3.
Increased bactericidal activity was observed on addition of inorganic cations to both acid and alkaline glutaraldehyde solutions. Mg2+ ion in particular potentiated activity and this was attributed to cell surface effects due to osmotic forces resulting in greater uptake of disinfectant, reduction in cell volume and interference with enzyme activity associated with the cell wall.  相似文献   
4.
In sandy clay loam under glass 11.2 kg a.i. Du Pont 1410 alone or with 448 kg Di-Trapex CP/ha, 441 kg dazomet with 448 kg Telone or 448 kg Di-Trapex CP/ha, prevented potato cyst-nematodes, Heterodera pallida, increasing on KNVF tomato rootstocks. In the heated glasshouse where the soil was treated with 441 kg dazomet/ha alone, the nematodes increased in the top 10 cm of soil, whether the soil was sealed with Polythene sheeting or water and whether dazomet was applied as dust or prill (small granules). Methyl bromide at 1276 kg/ha did not control the nematodes in soil 20–30 cm deep in one of the treated plots. Tomatoes grew well after all treatments except Du Pont 1410 which had little, if any, effect on grey sterile fungus (Pyrenochaeta lycopersici). Dazomet with Telone or dazomet with Di-Trapex CP inhibited root damage by the fungus.  相似文献   
5.
SUMMARY: A process for dehydrating fish under vacuum and in contact with heated plates is described. Although the conditions, in respect of time and temperature, appeared suitable for microbial development, a reduction in the number of bacteria usually occurred. A survey of the data accumulated over twenty months, including a series of experimental production periods, showed that the bacterial population estimated at 22° was reduced in the process as a whole to about 1% of its initial value and that estimated at 37° to about 10%. Species of the genus Micrococcus tended to predominate on the finished product. Contrary to earlier expectations, there should be no serious microbiological hazards if high standards of personal and factory hygiene are maintained.  相似文献   
6.
Aldicarb or Du Pont 1410 (S-methyl 1-(dimethylcarbamoyl)-N-[(methylcarbamoyl) oxy] thioformimidate) at 2.6–11.2 kg a.i./ha applied to the soil at planting time controlled potato cyst-nematode, Heterodera rostochiensis, in sandy loam, peaty loam and silt loam and greatly increased tuber yields of susceptible potatoes. Nemacur (O-ethyl-O-(3-methyl-4-methylthiophenyl) isopropylamido-phosphate) controlled potato cyst-nematode in sandy loam at 2.9–10.3 kg a.i./ha and in silt loam at 11.2 kg a.i./ha but did not control the nematode well in peaty loam even at 22.4 kg a.i./ha. In peaty loam aldicarb and Nemacur were more effectively incorporated by rotavation than by a modified power harrow.  相似文献   
7.
Labyrinthula     
SYNOPSIS. The bionomics of Labyrinthula Cienkowski and the validity of the family Labyrinthulidae Haeckel are reviewed. The structure, physiology (including nutrition), locomotion, ecology, and possible pathogenicity for eel-grass ( Zostera marina L.) are discussed. The uniqueness of its gliding motility along slime tracks, lack of phagotrophy, and poorly understood congregation tendencies emphasize the present taxonomic isolation of the group. Further interest attaches to some species because of their steroid requirements.  相似文献   
8.
9.
A total of 627 cattle representing seven breeds from south central Nebraska, USA were tested for 37 BoLA antigens which behave as products of 37 distinct alleles of the class I BoLA-A locus. Four antigens were absent from all breeds tested. The other antigens showed marked and statistically significant differences in breed distribution. There was no evidence for blank (null) alleles. The number of alleles in each breed ranged from 10 to 20. The Hereford and Simmental populations tested were less polymorphic than the Angus, Brown Swiss, Charolais, Gelbvieh and Limousin populations.  相似文献   
10.
    
Aldicarb, or Du Pont 1410 (S-methyl-I-(dimethylcarbamoyl)-N-[(methyl-carbamoyl)oxy]thioformimidate), at 2.8–22.4 kg a.i./ha incorporated in the seed-bed before sowing greatly increased the yield of peas in a clay loam and two sandy clay soils infested with pea cyst-nematode, Heterodera goettingiana, and lessened or prevented increase in the number of nematodes. CibaGeigy 10576 (an organophosphorus compound) at 5.6–22.4 kg a.i./ha was similarly effective in a sandy clay soil. Dowco 275 (O, O-diethylO-(6-fluoro-2 pyridyl) phosphorothioate) at 5.6 or 11.2 kg a.i./ha also controlled the nematode well in the clay loam and in a sandy clay soil but although it greatly increased the yield of peas in the clay loam, it did not increase yield in the sandy clay.  相似文献   
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