Carryover Concerns for 2013

One of the consequences of the current drought will be reduced herbicide degradation. In some situations, this prolonged persistence will lead to damage to the rotational crop next spring. The risk of carryover injury will vary widely from field to field depending on several factors (Table 1); thus, it is important to evaluate each field individually

Troublesome Palmer Amaranth Expanding Its Range

Many people are aware of the problems Palmer amaranth is causing farmers in the mid-south and southeast United States. Palmer amaranth is a close relative to Iowa’s number one weed problem – waterhemp. Like waterhemp, Palmer amaranth is a species with a propensity to evolve herbicide resistance. Glyphosate resistant Palmer amaranth devastated the cotton industry, which has fewer chemical options than available in corn and soybean. This article will describe Palmer amaranth and the risk of it appearing in Iowa

Weed management update for 2015

Given the environmental conditions in 2013 resulting in delayed herbicide applications and drought later in the summer, the increasing use of “alternative” herbicides and the cool wet conditions in 2014, conditions were excellent for many interesting occurrences. Herbicide carryover was a factor for several products, several products provided evidence why farmers preferred using glyphosate alone, and herbicide-resistant weed populations continue to evolve. It appears that the message of diversity in order to manage herbicide resistance is gaining traction but to the extent that the focus is primarily on herbicides which was the reason that herbicide resistance became such a big issue. There is a need to expand the acceptance of more diversity in weed management

The Effects of Chronic Hypercarbia on Morphological and Ventilatory Development in Crayfish

Instances of abnormally high CO2 levels are becoming increasingly common in freshwater ecosystems undergoing eutrophication. Chronic hypercarbia (long-term elevation of the partial pressure of carbon dioxide (Pco2)) is pervasive in these eutrophic ecosystems. Elevated Pco2 increases the ventilation and metabolism of some tadpoles and aquatic frogs and hinders their morphological development23. We expect that chronic hypercarbia will affect most aquatic organisms in the same way, but it remains to be verified that chronic hypercarbic conditions also alter aquatic organisms similarly to intermittent and acute hypercarbic challenges

Orientation effects in reactions of allenyl cations with styrene

Allenyl cations, generated from allenyl or alkynyl halides and Ag+, attack styrene at the side chain or at the aromatic nucleus. The allenyl/alkynyl product ratio is dependent on the structure of the precursor halide except for highly substituted systems

Farmer Awareness of Herbicide-resistant Weeds

One of the key concerns about managing pests, and specifically weeds, is time requirements. This reflects not only agricultural demographics such as farm size, but also whether individuals have off-farm job responsibilities. The distribution of farm sizes represented in the survey responses approached a normal distribution (Table 1) and is representative of the farm size distribution in Iowa based on recent information from the National Agricultural Statistics Service