A Study of the Phylogeny of the Anteoninae

A study of the biology of insect parasites and their relationships with that of their hosts offers a most attractive and productive field for research, and as yet, comparatively speaking, but little has been done in this field. This is particularly true with the Hymenoptera, and the writer has been interested in working out the biology of the Anteoninae, one of the parasitic groups of this order. These insects are parasitic on three families of the Homoptera, namely, the Cicadellidae, and Fulgoridae, commonly known as leafhoppers, and the Membracidae or treehoppers

Competing mechanisms of stress-assisted diffusivity and stretch-activated currents in cardiac electromechanics

We numerically investigate the role of mechanical stress in modifying the conductivity properties of the cardiac tissue and its impact in computational models for cardiac electromechanics. We follow a theoretical framework recently proposed in [Cherubini, Filippi, Gizzi, Ruiz-Baier, JTB 2017], in the context of general reaction-diffusion-mechanics systems using multiphysics continuum mechanics and finite elasticity. In the present study, the adapted models are compared against preliminary experimental data of pig right ventricle fluorescence optical mapping. These data contribute to the characterization of the observed inhomogeneity and anisotropy properties that result from mechanical deformation. Our novel approach simultaneously incorporates two mechanisms for mechano-electric feedback (MEF): stretch-activated currents (SAC) and stress-assisted diffusion (SAD); and we also identify their influence into the nonlinear spatiotemporal dynamics. It is found that i) only specific combinations of the two MEF effects allow proper conduction velocity measurement; ii) expected heterogeneities and anisotropies are obtained via the novel stress-assisted diffusion mechanisms; iii) spiral wave meandering and drifting is highly mediated by the applied mechanical loading. We provide an analysis of the intrinsic structure of the nonlinear coupling using computational tests, conducted using a finite element method. In particular, we compare static and dynamic deformation regimes in the onset of cardiac arrhythmias and address other potential biomedical applications

Bionomics and control of the potato leafhopper, Empoasca mali Le Baron

The potato leafhopper (Empoassca mali, LeB) is the most serious insect pest affecting the potato crop in Iowa, and probably in the Mississippi valley. Thru its feeding activities, it produces a pathological condition in the leaves of many of its host plants which is characterized by a distortion of the leaf veins, especially near the tip and a yellowing of the tissue supplied by them around the margin and at the tip. Often this yellowing is followed by a necrosis of the leaf tissue. Especially is this true on the potato and with this plant the burning is accompanied by a rolling upward and inward of the leaf margin

Control of the Potato Leafhopper

Potato fields In Iowa for several years have suffered from burning, which has seriously cut the yield of this crop. The trouble has been called tlpburn. Its cause was unknown until recently, when It was discovered that It Is due chiefly to the potato leafhopper, a little green, fly-llke Insect that appears In enormous numbers during the summer. The Iowa Agricultural Experiment Station has verified this connection between the leafhopper and tlpburn or hopperburn and control measures have been devised

Melon and Cucumber Insects

Probably the most important factor in the production of melon, cucumber, squash, pumpkin and other cucurbit plants in Iowa is the control of their insect enemies. Altho these plants are not liable to attack by many kinds of insect pests, they are frequently badly injured or even entirely destroyed by a very few destructive species. Some of these feed upon the foliage, others upon the flowers, while others bore into the stem or even into the roots. Much of the damage done by these pests may be prevented by applying the correct remedy at the proper time. Insects not only injured the plants directly by their feeding activities, but also indirectly because they may carry and inoculate healthy plant tissues, with serious disease producing organizations. The two most serious plant diseases carried by the melon aphid and striped beetle are bacterial wilt and mosaic disease

The Pink Bollworm of Cotton in Texas.

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Technical Note: Field experiences using UV/VIS sensors for high-resolution monitoring of nitrate in groundwater

peer-reviewedTwo different in situ spectrophotometers are compared that were used in the field to determine nitrate-nitrogen (NO3-N) concentrations at two distinct spring discharge sites. One sensor was a double wavelength spectrophotometer (DWS) and the other a multiple wavelength spectrophotometer (MWS). The objective of the study was to review the hardware options, determine ease of calibration, accuracy, influence of additional substances and to assess positive and negative aspects of the two sensors as well as troubleshooting and trade-offs. Both sensors are sufficient to monitor highly time-resolved NO3-N concentrations in emergent groundwater. However, the chosen path length of the sensors had a significant influence on the sensitivity and the range of detectable NO3-N. The accuracy of the calculated NO3-N concentrations of the sensors can be affected if the content of additional substances such as turbidity, organic matter, nitrite or hydrogen carbonate significantly varies after the sensors have been calibrated to a particular water matrix. The MWS offers more possibilities for calibration and error detection but requires more expertise compared with the DWS.The authors would like to acknowledge the Teagasc Walsh Fellowship scheme for funding the study in Ireland, and the German federal Ministry of Education and Research (BMBF) for sponsoring the SMART-project (grant no. 02WM1079-1086, 02WM1211-1212) for the study in Jordan.Teagasc Walsh Fellowship Programm

A Case of Arsenical Injury to Tomato Plants

On August 15, 1921, the writer was called to examine the tomato plants in one of the experimental plots of the Iowa State College Horticultural Department which were dying from some unknown cause. Upon examination, many plants were found showing all stages of what appeared to be some wilt disease. The caretaker stated that the trouble was manifested at first by a wilting of the entire plant which was often followed in a few days by its death. Upon examination, the first plant revealed the presence of a small mite in large numbers. These were found throughout the lower portions of the main stem and it was thought at first that these acari were the cause of the trouble. Subsequent examinations of other affected plants failed to disclose the mite in all cases and it was evident that this species was a secondary invader. Doctor J. C. Gilman, of the Plant Pathology section, was called and took specimens to his laboratory for further tests. He reported later that he could isolate no pathogenic organism