Quantitative impact assessment of spray coverage and pest behavior on contact pesticide performance

BACKGROUND: Standard procedures for evaluation of pesticide performance do not take into account pest behavioral response or incomplete spray coverage. In this study, a series of laboratory experiments was conducted with two non‐systemic miticides (propargite and hexythiazox) applied to cotyledon cotton plants, which were subsequently infested with spider mites. The results of these laboratory experiments are discussed through a comprehensive pest population dynamics model. RESULTS: When cotton leaves were submerged in miticide solutions, both miticides provided effective control of spider mites. In a two‐choice test it was demonstrated that propargite was repellent to spider mites, but not hexythiazox. Finally, the spray coverage on cotton plants was varied, and, for both miticides, significantly positive relationships between spray coverage and spider mite mortality were shown. However, propargite required higher spray coverage (20%) than hexythiazox (10%) to control spider mites. A theoretical model showed that, without repellency, the pesticide performance is positively correlated with target pest mobility. If the pesticide is repellent, the probability of exposure decreases, especially for a less mobile pest. CONCLUSION: With an experimental and theoretical modeling approach, it was demonstrated how the combination of behavioral avoidance and low spray coverage can markedly reduce pesticide performance. Copyright © 2012 Society of Chemical Industry     

Phosphate Fertilizers for Sugarcane Used at Pre-Planting (Phosphorus Fertilizer Application)

Phosphate applications are still rare in sugarcane cultivation and can be done with phosphorus fertilizers of residual over. This study aims to evaluate the agronomic efficiency of phosphate fertilization before sugarcane planting and its effect on sugarcane yield. The study was carried out over three crop cycles at the Jalles Machado sugar-mill in Goianésia, GO, Brazil. The treatments consisted of five different phosphorus sources (soluble and insoluble) applied at a rate of 300 kg ha^?1 phosphorus pentoxide (P₂O₅). The phosphorus fertilizers used were: triple superphosphate, mono-ammonium phosphate (MAP), Arad rock phosphate, Itafós rock phosphate, and magnesium term phosphate. The effects of these fertilizers were evaluated by plant height (ground to Top Visible Dewlap; TVD), leaf phosphorus content, agronomic efficiency, and sugarcane yield from cane-plants, first ratoon, and second ratoon. Magnesium term phosphate and triple superphosphate resulted in greater plant-cane height. Leaf phosphorus concentrations were highest with applications of MAP, magnesium term phosphate, and triple superphosphate. Phosphate applications did not affect sugarcane plant yield, but did increase ratoon yield. In general, the residual effect of insoluble phosphate increased over the years. The agronomic efficiency (AE) of phosphate was (in descending order): triple superphosphate (100%), term phosphate (89%), MAP (80%), Itafós rock phosphate (67%), and Arad rock phosphate (60%).     

Enzymatic solubilization of arabinoxylans from native, extruded, and high-shear-treated rye bran by different endo-xylanases and other hydrolyzing enzymes

The overall objective of this research was to find a new way to valorize rye bran, by producing a gellifier from the enzymatic solubilization of arabinoxylans (AX). The effects of three pure endo-xylanases from Aspergillus niger (Xyl-1), Talaromyces emersonii (Xyl-2), and Bacillus subtilis (Xyl-3) and of Grindamyl S100 (GS100), a commercial enzyme preparation containing a Xyl-1 type endo-xylanase, were tested on rye bran to study the solubilization of water-unextractable arabinoxylans (WUAX). Eight different extrusion-treated rye brans were also used as substrates to find the best physical treatment to facilitate enzymatic arabinoxylan (AX) solubilization. Arabinoxylans were better solubilized from the bran extruded at high temperature using Xyl-3. This enzyme was then tested in combination with pure (1,4)-beta-d-arabinoxylan arabinofuranohydrolase (AXH) and endo-beta-d-glucanase or ferulic acid esterase (FAE), from A. niger. Only beta-glucanase in combination with Xyl-3 improved the AX extraction, but it did not have a marked effect on the viscosity of the extracts. Xyl-3 was then tested on a high-shear-treated rye bran, and results were compared to those obtained with the high-temperature-extruded rye bran. The high-shear treatment did not improve the bran AX enzymatic solubilization. The combination of FAE with Xyl-1 or Xyl-3 did not improve the AX extraction from untreated and high-shear-treated rye bran. Finally, to study the gelation capacity of the enzymatically solubilized AX, the effect of the hydrogen peroxide/horseradish peroxidase (H(2)O(2)/POD) was tested on the Xyl-3 high-temperature-extruded bran extracts. Solubilized AX did not gel in the presence of the oxidizing system.     

Badger hair in shaving brushes comes from protected Eurasian badgers

The Eurasian badger (Meles meles) is included in Appendix III of the Bern Convention and protected by national laws in many European countries. Badger hair is used to manufacture luxury shaving brushes, although it is frequently argued that the hog badger (Arctonyx collaris), which in Europe is an introduced and unprotected species, is the origin of the hair used. We applied an extraction protocol to recover DNA from the unrooted hair of shaving brushes obtained from commercial companies in The Netherlands and Spain. The tested brushes originated from The Netherlands, Spain, France, Italy and the United Kingdom where the Eurasian badger is a protected species. We sequenced 191 bp of the mitochondrial DNA control region and 170 bp of the cytochrome b gene and compared the sequences obtained with Eurasian badger and hog badger reference sequences of the same mitochondrial DNA regions obtained in our laboratory and from GenBank. Sequences obtained from four shaving brushes were clearly hog badger sequences, whereas four sequences clustered with Eurasian badger sequences of both European and Asian origins. One of the shaving brushes made of Eurasian badger was produced in France, where it is legal to capture or trade the species under certain conditions. The remaining three brushes originated from The Netherlands, where it is illegal to possess, sell, transport or use for commercial purposes dead Eurasian badgers or products derived from them.     

Grape-seed procyanidins act as antiinflammatory agents in endotoxin-stimulated RAW 264.7 macrophages by inhibiting NFkB signaling pathway

Procyanindin extract (PE) is a mixture of polyphenols, mainly procyanidins, obtained from grape seed with putative antiinflammatory activity. We evaluated the PE effect on RAW 264.7 macrophages stimulated with lipopolysaccharide plus interferon-gamma that show a rapid enhanced production of prostaglandin E2 (PGE2) and nitric oxide (NO). Our results demonstrated that PE significantly inhibited the overproduction of NO, dose and time dependently. PE caused a marked inhibition of PGE2 synthesis when administered during activation. Moreover, PE pretreatment diminished iNOS mRNA and protein amount dose dependently (10-65 microg/mL). PE (65 microg/mL) pretreatment inhibited NFkappaB (p65) translocation to nucleus by nearly 40%. Trimeric and longer oligomeric-rich procyanidin fractions from PE (5-30 microg/mL) inhibited iNOS expression but not the monomeric forms catechin and epicatechin. Thus, we show that the degree of polymerization is important in determining procyanidin effects. PE was considerably a more effective inhibitor of NO biosynthesis (IC50 = 50 microg/mL) in comparison to other antiinflammatories, such as aspirin (3 mM), indomethacin (20 microM), and dexamethasone (9 nM). In conclusion, PE modulates inflammatory response in activated macrophages by the inhibition of NO and PGE2 production, suppression of iNOS expression, and NFkB translocation. These results demonstrate an immunomodulatory role of grape seed procyanidins and thus a potential health-benefit in inflammatory conditions that exert an overproduction of NO and PGE2.     

Assessing insecticide and fungicide effects on the culturable soil bacterial community by analyses of variance of their DGGE fingerprinting data

To assess the effects of three insecticides (aldicarb, chlorpyrifos, deltamethrin) and two fungicides (tebuconazole and metalaxyl + mancozeb) on the PCR-DGGE fingerprints of culturable soil bacterial communities (CSBC), a greenhouse experiment was carried out with soil samples from an Integrated System for Agroecological Production (ISAP), a Conventional Potato Production Area (CPPA) and a Secondary Forest Area (SFA) close to the CPPA. Samples were obtained at 15 day intervals starting at 32 until 77 days after sowing (DAS) to perform the PCR-DGGE analysis of the CSBC cultured on media amended with soil suspension. Analysis of variance from PCR-DGGE data indicated significant differences among treatments. Regardless the type of pesticide applied, CSBC was disturbed and similarity values varied from 5% to 90% in comparison to the control. Significant shifts on CSBC were only detected among treatments in the first two harvests, while CSBC tended to be more akin to each other at the last two harvest dates. The most significant responses observed were due to different soil sample origins, where values of 5% of similarity to the control were observed on CPPA soil. The use of analysis of variance on PCR-DGGE data was useful to a better understanding of the changes on CSBC induced by pesticides applications.