Grow them and we will come for the feast

Sustainable production of switchgrass and other bioenergy grasses will require eff ective pest management. Identifi cation of potential insect pests and detailed characterization of the plant-insect interaction will better enable us to address emergent insect pests in production fi elds. An added uncertainty is how manipulation of plants for improved quality (e.g. lower lignin) will aff ect plant resistance to insect herbivory. Plants can utilize different mechanisms to defend against chewing versus piercing-sucking insects; however, some basal plant responses appear to be shared across diverse biotic stressors. Th e range and modulation of these responses are beginning to be addressed for several of the temperate, perennial, warm-season grasses that are designated as biomass crops. Other systems have demonstrated the need to become proactive in these studies. For instance, buff alograss, Buchloë dactyloides (Nuttall) Engelmann, was fi rst introduced as a low-maintenance turf species. However, a number of important insect pests were documented within a relatively short time frame.1,2 Similarly, several recent reports have been published for switchgrass (Panicum virgatum L.) and Miscanthus (Miscanthus x giganteus) that indicate the presence of insect pests in production fi elds, and the overall susceptibility of these species to insect herbivory.3-

Rotation Resistant Rootworms 2007

Corn rootworms have been, and in many cases still can be, managed with crop rotations. However, some populations of both northern and western corn rootworms (CRWs) have adapted to the corn-soybean rotation. Regular, annual rotations between corn and soybeans have selected for a variant of the northern CRW that has a two-year life cycle, referred to as extended diapause. Female northern CRWs deposit eggs in the soil within cornfields. When the field is rotated to soybean the next year, most eggs hatch and the larvae starve. However, a portion of the eggs remain dormant in the soil for a second winter and do not hatch until the following spring when corn is planted back into the field resulting in damage to the rotated corn. Extended-diapause northern CRWs originally caused severe injury to rotated corn in NW Iowa, SW Minnesota, SE South Dakota, and NE Nebraska during the late 1980s. Since then their range has expanded until it is now found throughout most of Iowa. South Dakota has estimated that nearly 50% of their northern CRWs are the extended-diapause variant. Data from the 2005 & 2006 monitoring program has concluded that extended diapause is present throughout eastern Iowa. This information, in combination with previous surveys, confirms that extended diapause is present at some level in all parts of that state. Although its presence has been confirmed throughout the state, its relative abundance may be changing

Is the Biology of Corn Rootworms Changing in Iowa?

In east central Illinois during the summer of 1995, corn planted where soybeans had been grown the previous season was seriously damaged by the western corn rootworm (Diabrotica virgifera virgifera). Since then a variant of the western corn rootworm (often referred to as the eastern variant of the western corn rootworm ) that infests corn grown in rotation has spread throughout the northern half of Illinois, western Indiana, and southern Wisconsin and Michigan. The larvae of the variant are able to attack rotated corn because the adults no longer maintain their fidelity to corn as the preferred crop for egg laying; they will oviposit in other crops including soybeans. When corn is planted following the rotational crop, the soil is infested with eggs and the larvae that emerge find corn roots to attack and develop on. In the areas where the variant is found, damage to rotated corn has been severe. The lodging and yield losses have resulted in a dramatic increase in the use of insecticides, and a corresponding increase in production costs in rotated corn where little insecticide was applied for corn rootworm control prior to 1995

Rotation-Resistant Corn Rootworms 2006

Corn rootworms have been, and in many cases still can be, managed with crop rotations. However, some populations of both northern and western corn rootworms (CRWs) have adapted to the com-soybean rotation. Regular, annual rotations between corn and soybeans have selected for a variant of the northern CRW that has a two-year life cycle, referred to as extended diapause. Female northern CRWs deposit eggs in the soil within cornfields. When the field is rotated to soybean the next year, most eggs hatch and the larvae starve. However, a portion of the eggs remain dormant in the soil for a second winter and do not hatch until the following spring when corn is planted back into the field resulting in damage to the rotated corn. Extended-diapause northern CRWs originally caused severe injury to rotated corn in NW Iowa, SW Minnesota, SE South Dakota, and NE Nebraska during the late 1980s. Since then their range has expanded until it is now found throughout most of Iowa. South Dakota has estimated that nearly 50% of their northern CRWs are the extended-diapause variant

Reassessing Physical Ability Testing for Police Officers

A declining applicant pool of police officer candidates is a major issue facing law enforcement. The challenge for law enforcement is to evaluate ways to increase applicant pools. History in law enforcement suggests that qualified candidates have been eliminated from consideration for various reasons that were later discovered to be inaccurate. A current segment of the population, namely disabled persons, seem to be mirroring the fate of prior candidates. They are being eliminated from consideration for employment as police officers because of invalid physical ability testing standards. Law enforcement agencies should reassess existing pre-employment physical ability testing standards for police officers to make certain the measures tested are validated and meet the job requirements for the positions. Discussion will center on the physical ability tests and their applicableness to the actual essential tasks being performed. An evaluation of the American with Disabilities Act and other discrimination laws as it relates to physical ability testing will result in demonstrating that many law enforcement agencies may be in violation of federal law. In addition, discussion will center on the assertion that many persons with disabilities often adapt to their environment and most probably, with the ongoing technological advancements, could adapt to the essential functions of the position of police officer. The conclusions, based on the research, results in a suggestion that law enforcement evaluate current physical ability standards to affirm that they are valid and based on scientific data for each respective agency. In addition, the proposition advises that agencies continually assess their physical ability standards testing to ensure compliance with the American with Disabilities Act and other discrimination laws

Rotation-resistant corn rootworms in Iowa

There are variants of both corn rootworm species in Iowa that are resistant to crop rotation. The northern corn rootworm overcame the annual rotation of corn with another crop by developing a two-year life cycle. This variety of the northern corn rootworm (known as extended diapause) became common and caused extensive damage to rotated corn in the late 1980s in northwest Iowa. Since then it has spread throughout Iowa and is probably found in every county

The role of grain sorghum in conservation of predatory arthropods of Texas cotton

Four separate but complimentary studies investigated the role of grain sorghum as a predator source for Southern Rolling Plains cotton in 2001 and 2002. Objectives were to: (1) determine the timing and magnitude of predator movement between crops, (2) test putative causes of movement by manipulating prey levels at different stages of crop phenology, (3) explore the feeding and reproductive behavior of a common predator colonizing cotton, and (4) examine the effects of grain sorghum and uncultivated areas on cotton predator abundance at an area-wide scale. Rubidium mark-recapture experiments indicated grain sorghum fields produced a net predator gain for adjacent cotton. Analysis suggested two coccinellids, Hippodamia convergens Guérin-Méneville and Scymnus loewii Mulsant, were responsible for the overall pattern of predator movement. Predator movement into cotton did not appear to be concentrated at specific stages of sorghum phenology. Manipulations of aphid levels in field cages were used to determine if prey abundance or phenology influenced the movement of H. convergens into cotton. In both years, more lady beetle adults were collected on cotton during the latest stages of sorghum phenology. In the second year, relatively low aphid densities (15 per plant) appeared to influence the movement of beetles onto caged cotton. Carbon isotope ratios of H. convergens were used to assess adult feeding behavior after colonizing cotton and to determine if prey consumed in sorghum contributed to egg production in cotton. Though aphids were absent 2001, H. convergens adults stayed in cotton, did not produce eggs and apparently consumed few prey. Cotton aphids were present in 2002 and H. convergens isotope ratios changed from prey consumed in cotton. The isotope ratios of egg masses collected in 2002 indicated prey consumed in grain sorghum contributed very little to egg production in cotton. An area-wide pattern analysis suggested the abundance of grain sorghum and uncultivated areas both positively influenced cotton predator levels. While these landscape effects were less important overall than prey levels and cotton planting dates, in some sampling periods landscape composition appeared to be the most important factor in determining cotton predator levels