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Biomedical subjects

J K Olson

Publications and source records attributed to J K Olson.

69 records · Page 4Linked to original sources
PubMed1986

Occurrence of Psorophora columbiae eggs in different field types comprising a Texas riceland agroecosystem.

Soil samples (3,258) were collected from soybean fields, rice fields and permanent pastures in Chambers County, TX over a 2 1/2-year period and examined for the presence of Psorophora columbiae eggs. Eggs occurred more frequently and in greater numbers in samples taken from soybean fields than in samples from either rice fields or permanent pastures during the summers of 1979 and 1981 when there was heavy rainfall in the study area. Under dry conditions, as during the summer of 1980, the frequency of egg occurrence and abundance increased in samples taken from rice fields. However, egg occurrence and abundance in soybean field samples still remained relatively high even during this particular year.

Agriculture↗
PubMed1986

Combination ground and aerial adulticide applications against mosquitoes in an Arkansas riceland community.

Simultaneous ground and aerial adulticide applications were evaluated against riceland mosquitoes in Stuttgart, AR, during July 1985. Naled was aerially applied at 52.6 ml/ha over 10.4 km2 surrounding the city. Ground ULV applications of a mixture of malathion, HAN and resmethrin/PBO (1:1:0.0625) were applied within the city at a rate of 221.8 ml/min at 24 kph. Adult populations of Anopheles quadrimaculatus and Psorophora columbiae were reduced at 24 hr but resurgence of Ps. columbiae was evident at 48 hr posttreatment. Posttreatment data indicated that movement of both mosquitoes occurred along the path of prevailing wind.

Agriculture↗
PubMed1986

Temporal abundance and percent insemination of newly-emerged adult female Psorophora columbiae near the larval habitat.

The temporal abundance and percent insemination of newly-emerged adult female Psorophora columbiae were investigated in riceland sites near Anahuac, TX. Pre- and postmating nights were characterized by low numbers of females and little mating activity (no significant increase in percent insemination) occurring in the study site. Mating nights were characterized by high female abundance in the study site before sunset then steadily decreased until a stable, low level of abundance was reached approximately 2 to 2.5 hr after sunset. On mating nights, percent insemination of female mosquitoes in the study site remained low until sunset, after which it steadily increased until a maximum was reached about 2 hr after sunset. On each mating night, approximately 2 to 2.5 hr after sunset, a mass exodus from the site by primarily mated females with some males was observed.

Agriculture↗
PubMed1986

Effects of sound on swarming male Psorophora columbiae.

Male Psorophora columbiae were shown to respond to sound during swarming. The responses consisted of abrupt changes in flight speed and direction. Tones with frequencies of 200 to 425 Hz were attractive to males over a distance of at least 1 m. Male mosquitoes responded better to tones with sine waveforms than they did either to square waveforms or triangular waveforms. Swarming males became accommodated and no longer responded to sounds presented for 5 seconds or longer. Based on observations of field populations of swarming Ps. columbiae, it appears that males use sound waves to locate females, but additional factors seem to be required for males to initiate the actual copulatory behavior. Also, males appear to use sound to maintain their position and spatial relationship within the swarm.

Animals↗
PubMed1985

Effects of sprinkle irrigation on the occurrence and abundance of Psorophora columbiae eggs in ricelands.

Low-pressure sprinkler irrigation was investigated as to its potential influence on the frequency of occurrence and relative abundance of Psorophora columbiae eggs in Texas ricelands. Analysis of egg sampling data collected from soybean, rice and sorghum field sites subjected to either sprinkle or flood irrigation practices during 1982-83 indicated no significant differences in either the frequency of occurrence or relative abundance of Ps. columbiae eggs in the various sites. Data collected during 1984 indicate that the amount of water applied to a field by a sprinkler system will have some influence on the numbers of Ps. columbiae eggs occurring in the field. The frequency of occurrence and relative abundance of Ps. columbiae eggs occurring in field sites sprinkle-irrigated at full-pan evaporation rates (i.e., all moisture in the soil lost to evaporation was replenished via irrigation) were significantly higher than was the case in the sites irrigated at half-pan and quarter-pan rates.

Agriculture↗
PubMed1985

The effects of selected rice and soybean pesticides on the eggs of Psorophora columbiae.

Twenty-five pesticides used in the production of rice and soybeans in Texas were tested in the laboratory to determine their toxicity to the eggs of Psorophora columbiae. A reduction in hatching rate occurred when eggs were treated with a herbicide formulation containing thiobencarb and with one containing a tank mixture of propanil and molinate. A carbaryl formulation induced hatching of eggs prior to their exposure to the hatching stimulus. Reduced survival to second instar of larvae hatching from treated eggs was observed with insecticide formulations of acephate, carbofuran, malathion, methyl parathion and toxaphene; a fungicide formulation of triphenyltin hydroxide and the tank mixture of the herbicides, propanil and molinate.

Animals↗
PubMed1985

Observations on male swarms of Psorophora columbiae in Texas ricelands.

The evening swarming behavior of newly emerged male Psorophora columbiae was studied in eastern Texas ricelands. Near infrared-sensitive video equipment was used to record swarming as it occurred in the field during each night of observation. Males of Ps. columbiae form either funnel-like or curtain-like marker swarms over a variety of objects in a riceland habitat. The sequence of events leading to swarm formation is described. Swarming males fly into the wind and follow a figure-8 pattern of flight. This flight pattern is modified by other insects flying through or near the swarm. Sudden changes in wind velocity or direction also modify the position and shape of the swarm relative to the marker over which it has formed.

Animals↗
PubMed1985

Evaluation of Beecomist-applied Bacillus thuringiensis (H-14) against Anopheles quadrimaculatus larvae in rice fields.

The Beecomist spray head was evaluated for aerial application of Bacillus thuringiensis var. israelensis (serotype H-14; Bti) at various ultra low volume (ULV) rates against natural populations of Anopheles quadrimaculatus larvae in rice fields. Deposits on Kromekote cards indicated that 0.54 liter/ha of neat Bti penetrated the dense canopy of the rice field. Mean number of droplets 65 cm below canopy level was 4.9 +/- 5.0/100 cm2. At 1 day posttreatment, applications of 0.54, 0.27, 0.11, 0.07 and 0.04 liter of Bti/ha resulted in reductions of 97.9, 94.4, 93.0, 71.1 and 21.8%, respectively, of An. quadrimaculatus larvae/dip. Calculated lethal field dosages (LFD50 and LFD90) were 0.05 and 0.16 liter/ha, respectively.

Animals↗