Velvetbean and Bahiagrass as Rotation Crops for Management of Meloidogyne spp. and Heterodera glycines in Soybean.

Soybean (Glycine max) yield often is limited by the phytoparasitic nematodes Meloidogyne spp. and Heterodera glycines in the southeastern United States. We studied the effects of rotation with bahiagrass (Paspalum notatum), velvetbean (Mucuna pruiens), or continuous soybean, aldicarb, and soybean cultivar on yield and population densities in two fields infested with a mixture of Meloidogyne spp. and H. glycines. Velvetbean and bahiagrass reduced population levels of both nematode species to near zero prior to planting soybean. At harvest, both nematode populations were equal in soybean following bahiagrass and continuous soybean but were lower following velvetbean. Both bahiagrass and velvetbean as previous crops were equal in producing significantly (P < 0.003) higher yield than continuous soybean. Velvetbean increased subsequent soybean yield by 98% and bahiagrass increased subsequent soybean yield by 85% as previous crops compared to continuous soybean. The major differences between the two rotation crops were yield response of the nematode-susceptible cultivars and at-harvest nematode populations. Velvetbean tended to mask genetic differences among cultivars more so than bahiagrass. Velvetbean also produced a more long-term effect on nematode populations, with numbers of both Meloidogyne spp. and H. glycines lower in soybean following velvethean than following bahiagrass or continuous soybean.

Electromyographic and nerve block analysis of the subscapularis liftoff test.

The inability to perform the "liftoff" test has been attributed to a subscapularis muscle or tendon injury. The goals of this study were to evaluate the activity of the glenohumeral muscles during performance of the "liftoff" maneuver and to identify the most effective initial upper extremity placement that isolates the subscapularis musculotendinous unit. In the first phase of this study 15 subjects accomplished four proposed versions to the "liftoff" test while their intramuscular electromyographic activity in select glenohumeral muscles was recorded. The second phase of this study assessed the ability of five subjects with a nonfunctional subscapularis musculotendinous unit to perform the same proposed versions. On the basis of electromyographic data none of the proposed versions to the "liftoff" maneuver isolated the upper and lower subscapularis muscle from either the teres major, latissimus dorsi, posterior deltoid, or rhomboid muscles (p > 0.05). In the presence of a nonfunctional subscapularis musculotendinous unit, the subjects were able to perform all of the proposed versions of the "liftoff" maneuver except one: elevation of the dorsum of the hand from the posterior-inferior border of the scapula (maximum internal rotation test). Although significant electromyographic activity was generated in the potentially confounding shoulder girdle muscles during the maximum internal rotation "liftoff" test, a successful test appears to be dependent on the isolated glenohumeral internal rotation function of the subscapularis muscle.

Comparison of Crop Rotation and Fallow for Management of Heterodera glycines and Meloidogyne spp. in Soybean.

The effects of cropping systems (fallow, rotation with sorghum-sudangrass hybrid [Sorghum bicolor x S. sudanense], and continuous soybean [Glycine max]), nematicide (aldicarb) treatment, and soybean cultivar on yield and nematode population densities were studied in a field infested with a mixture of Meloidogyne spp. and Heterodera glycines. Soybean following sorghum-sudangrass yielded 111 kg/ha more than soybean following fallow and 600 kg/ha more than continuous soybean. Aldicarb treatment increased yield by 428 kg/ha, regardless of previous crop. Cultivars interacted significantly with nematicide treatment and previous crop with respect to yield. Sorghum-sudangrass reduced numbers of Meloidogyne spp. compared with fallow and continuous soybean, but cropping system did not affect H. glycines numbers. The cultivar x previous crop and cultivar x nematicide interactions were significant for numbers of Meloidogyne spp. and H. glycines. We concluded that sorghum-sudangrass hybrid and fallow are effective in reducing yield losses caused by mixed populations of Meloidogyne and H. glycines. Highest yields were obtained using crop rotation and cultivars with the highest levels of resistance to both nematodes.

Velvetbean in Rotation with Soybean for Management of Heterodera glycines and Meloidogyne arenaria.

The effect of previous crops - soybean (Glycine max) or velvetbean (Mucuna deeringiana) - and aldicarb on yield and nematode numbers for selected soybean cultivars was studied in a field infested with a mixture of Meloidogyne arenaria and Heterodera glycines. Soybean following velvetbean yielded 959 kg/ha more than soybean following soybean. Nematicide treatment resulted in increased yield, and there was no interaction between nematicide treatment and previous crop. Cultivars interacted significantly with nematicide treatment but not with previous crop for yield. Velvetbean reduced numbers of H. glycines but not M. arenaria. Cultivars interacted with previous crop, and the previous crop x nematicide x cultivar interaction was significant for both M. arenaria and H. glycines. We concluded that velvetbean is effective in reducing yield losses caused by mixed populations of M. arenaria and H. glycines, regardless of genetic resistance of soybean cultivar.

Rotations of soybean with tropical corn and sorghum for the management of nematodes.

The relative efficacy of rotations of soybean with sorghum and tropical corn for nematode management was studied for 2 years in a field infested with root-knot (Meloidogyne arenaria) and soybean cyst (Heterodera glycines, race 14) nematodes. Corn, sorghum, and soybean cv. Kirby were planted in 1989, and in 1990 the same areas were planted with seven soybean cultivars with and without at-plant application ofaldicarb. Corn and sorghum did not support H. glycines, but significant juvenile populations of the nematode in soil were associated with Kirby soybean. Numbers of H. glycines and M. arenaria juveniles in 1990 depended on cultivar and cropping system but were little affected by nematicide treatment. Lowest numbers of H. glycines juveniles were associated with Leflore soybean and the corn-soybean rotation. Numbers of M. arenaria juveniles were highest with Leflore and lowest with Braxton and Brim soybean. The sorghum-soybean rotation resulted in slightly higher numbers of M. arenaria juvenile populations than soybean monoculture or the corn-soybean rotation. Aldicarb increased yields of some cultivars, but its use was not justified economically. Yields of all cultivars were from 19-287% higher in rotation systems than in monoculture.

Long-Term Effect of Crop Rotation on Soybean in a Field Infested with Meloidogyne arenaria and Heterodera glycines.

Previous cropping sequence (corn-soybean vs. soybean-soybean) and aldicarb effects on soybean yield and nematode numbers at harvest for soybean cultivars with various combinations of nematode resistance were determined in 1988 in a sandy loam soil infested with Meloidogyne arenaria race 2 and Heterodera glycines races 3 and 4 at Elberta, Alabama. Yield and nematode numbers differed among cultivars with 'Leflore' having the highest yield. Aldicarb treatment resulted in increased soybean yield but did not affect nematode numbers. Previous cropping sequence did not affect soybean yield or numbers of H. glycines, but soybean following corn-soybean had higher numbers of M. arenaria than soybean following soybean-soybean. The only significant statistical interaction was aldicarb x cultivar for numbers of H. glycines.

Effect of Crop Rotation on Soybean in a Field Infested with Meloidogyne arenaria and Heterodera glycines.

The effect of previous crops--soybean (Glycine max) or corn (Zea mays)--and aldicarb (2.2 kg a.i./ha) on yield and nematode numbers at harvest for soybean cultivars with various combinations of nematode resistance was determined in a sandy loam soil infested with Meloidogyne arenaria race 2 and Heterodera glycines races 3 and 4 at Elberta, Alabama, in 1987. Cultivars had an effect on yield and nematode numbers (P = 0.01), as did the interaction of previous crop and cultivar. The nematicide treatment x cultivar interaction was significant for yield, and the three-way interaction was significant for numbers of M. arenaria. A previous crop of corn had no effect on M. arenaria numbers, but it reduced numbers of H. glycines from 93 to 25 J2/100 cm(3) of soil and increased soybean yield from 1,963 to 2,560 kg/ha. Aldicarb reduced M. arenaria numbers from 230 to 186 J2/100 cm(3) soil and increased yield from 2,062 to 2,460 kg/ha but it had no effect on H. glycines numbers. Rotation with corn was an effective control measure for H. glycines and enhanced the yields of H. glycines-susceptible cultivars.

Soybean Response to Ethylene Dibromide in a Soil Infested with Meloidogyne arenaria and Heterodera glycines.

One susceptible and six nematode-resistant soybean cultivars were evaluated in the field for their effects on seed yield, nematode populations, and response to the fumigant nematicide, ethylene dibromide. The soil was a loamy sand infested with Meloidogyne arenaria and Heterodera glycines. Cultivars significantly affected yield and numbers of H. glycines but did not affect M. arenaria numbers. Fumigation increased yield and reduced M. arenaria numbers but did not affect numbers of H. glycines. The interaction between cultivars and fumigation was significant for yield but not for nematode numbers.

The MIE Carden ventilator. A description and laboratory assessment.

The Carden ventilator is described and assessed when used in adult and paediatric modes against test lungs with varying compliance and airways resistance. The ventilator proved to have limited ability to compensate for changes in test lung compliance and resistance. Repeated confirmation of tidal volume is mandatory, but the Carden combines simplicity with flexibility of design and may prove useful as a theatre ventilator.

Introduction of central venous pressure catheters through arm veins with a high success rate.

Studies were carried out to develop a more successful method of inserting central venous catheters through arm veins without using electrocardiographic or fluoroscopic monitoring. It was found that a running infusion attached to a Sorensen catheter gave a success rate of 48 per cent. The highest success rates (98 per cent) occurred when the basilic vein was used, with the patient positioned so that the upper part of the body was raised at 45-90 degrees to the horizontal and using a Bardic 16 gauge catheter with a special insertion technique, which is described. This represents a great improvement over the usual success rate of 70 to 80 per cent.

Further studies of manually operated self-inflating resuscitation bags.

Four resuscitators were tested, of which three had recently been improved by the manufacturers (Danish-made Ambu, Air Bird, Laerdal Resusci 2), and one was new (Hope 2). All functioned well at extremes of temperature and all would deliver 100 percent O2 to the patient. All are essentially vice-free and represent great steps forward in resuscitator design.

Dynamics of local-anesthetic compounds in regional anesthesia.

The clinical effectiveness and safety of compounded mixtures of lidocaine + bupivacaine and chloroprocaine + bupivacaine for either epidural or brachial-plexus block was studied in 48 adult patients. Of the several alternatives, chloroprocaine + bupivacaine with epinephrine was found the best choice for patients with typical plasma cholinesterase.

An improved percutaneous jetting system for use during microlaryngeal operations.

Studies carried out in the laboratory have shown that an S-shaped cannula for trans-laryngeal jet ventilation provides a distinct advantage over conventional straight ones. Tidal volumes are larger and the cannula is more stable in position. The tendency of perforate the posterior wall of the trachea during introduction is also minimal. Blood gas data obtained from patients being operated upon with this technique of anaesthesia show that it provides very adequate ventilation and can be effectively used with balanced anaesthesia if a nitrous oxide-oxygen blender is incorporated into the jetting system. It can be put in position before induction of anaesthesia to enable preoxygenation and assist ventilation and can be left in place at the end of the operation until the patient is breathing adequately. If necessary, a tracheostomy can be done with the cannula in situ. It is not proposed that this should be the standard mode of anaesthesia or ventilation for patients undergoing operations on the larynx, but in stituations where other methods are not adequate and when significant upper airway obstruction is present, this is an excellent alternative.