Mitigating the greenhouse gas emissions that arise durin manure is a crucial environmental challenge. We evalu effects of liquid manure timing (fall vs. spring) and nitrifi [2-chloro-6-(trichloromethyl) pyridine (nitrapyrin) vs. 3 phosphate (DMpp)] on n 2 O emissions, soil mineral n ley (Hordeum vulgare L.) productivity, and n uptake. E established in an incomplete split-plot design in Laco AB, Canada. Repeated measurements included n 2 O flu chambers, and soil ammonium (nH 4 -n) and nitrate (nO Relative to the manured soils without nIs, the use of n significantly reduced annual n 2 O emissions by 81% w with nitrapyrin in our Lacombe site; however, this diffe in the comparable spring treatments applied during the These beneficial effects were discernable in Lacombe, wetter than Edmonton, indicating the overriding role o n dynamics and fluxes. Following a 5-mo freezing wi caused at least 64% of annual n 2 O emissions from the f these intense episodic fluxes also revealed that the effic still continued during the early spring. On average, fal the n 2 O direct emission factors by about threefold com sponding spring treatments. Thus implementing liquid m nIs at the right timing has the potential opportunity to crops and simultaneously diminish global warming effect Abbreviations: CT, control treatment where the soil was disturb without soil disturbance); DM, dry matter; DMPP, 3, 4-dimethyl direct emission factors; FMD, fall-manured soil with DMPP, FMN nitrapyrin; FMW, fall-manured soil with no nitrification inhibitors; SMD, spring-manured soil with DMPP; SMN, spring-manured so spring-manured soil with no nitrification inhibitors.

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Abstract. Varroa destructor is a parasitic mite of the honey bee species Apis cerana Fabr. and A. mellifera L. Mature females reproduce on the immature stages of their hosts, producing more viable female offspring on drone hosts than on worker hosts. Thus, immature drones are more likely to be infested with mites than immature workers. To investigate the hypothesis that differences in host chemistries underlie the biased distribution of mites between worker and drone brood, the arrestment responses of mites to solvent extracts of a number of stimuli normally encountered by a mite during its life cycle were measured. Mites were arrested by cuticular extracts of worker and drone larvae obtained at 0, 24 and 48 h prior to the time when cell capping is completed. Mites were also arrested by extracts of worker and drone, brood food and cocoons, and by a blend of synthetic fatty acid esters previously shown to be active in the host acquisition process. In a wind tunnel bioassay, mites were attracted to odours from living fifth‐instar worker and drone larvae, but not to volatiles from cocoons, brood food or a blend of fatty acid esters. The sex of the host was not an important factor affecting the behavioural responses of the mites in any assay. We conclude that host kairomones play a role in the host acquisition process, but we found no evidence to support the hypothesis that mites use these substances to differentiate between worker and drone brood.

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Adult Diabroticites including western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, consume pollen of corn, squash, sunflower, and other species. Short-chain neutral amino acids in methanol-water extracts of pollen have been previously identified in our laboratory as strong phagostimulants for Diabrotica. Bioassay-driven fractionation was used to characterize the interacting lipid and midpolarity phagostimulants for adult WCR in Giant Gray Stripe sunflower, Helianthus annuus L., pollen. Lipids rich in omega3-linolenic acid including triglycerides, free fatty acids, phosphatidylethanolamines, phosphatidic acids, and phosphatidylcholines were highly phagostimulatory. Other important phagostimulatory components included a hydroxycinnamic acid-polyamine amide, N(1),N(5),N(10)-tri[(E)-p-coumaroyl]spermidine, and a flavonol, quercetin beta-3-O-glucoside. The structural characteristics of these phagoactive compounds and their role in the pollinivory specialization of rootworm beetles are discussed.

Abstract. Reductions in N2O emissions from nitrification inhibitors (NI) are substantial but remain uncertain because measurements of N2O emissions are highly variable and discontinuous. Mathematical modelling may offer an opportunity to estimate these reductions if the processes causing variability in N2O emissions can be accurately simulated. In this study, the effect of NI was simulated with a simple, time-dependent algorithm to slow NH4+ oxidation in the ecosystem model ecosys. Slower nitrification modelled with NI caused increases in soil NH4+ concentrations and reductions in soil NO3- concentrations and in N2O fluxes that were consistent with those measured following fall and spring applications of slurry over 2 years from 2014 to 2016. The model was then used to estimate direct and indirect effects of NI on seasonal and annual emissions. After spring slurry applications, NI reduced N2O emissions modelled and measured during the drier spring of 2015 (35 % and 45 %) less than during the wetter spring of 2016 (53 % and 72 %). After fall slurry applications, NI reduced modelled N2O emissions by 58 % and 56 % during late fall in 2014 and 2015 and by 8 % and 33 % during subsequent spring thaw in 2015 and 2016. Modelled reductions were consistent with those from meta-analyses of other NI studies. Simulated NI activity declined over time so that reductions in N2O emissions modelled with NI at an annual timescale were relatively smaller than those during emission events. These reductions were accompanied by increases in NH3 emissions and reductions in NO3- losses with NI that caused changes in indirect N2O emissions. With further parameter evaluation, the addition of this algorithm for NI to ecosys may allow emission factors for different NI products to be derived from annual N2O emissions modelled under diverse site, soil, land use and weather.

-We collected mites on boards coated with Vaseline; then, Vaseline, mites and debris were removed and solvent processed. Three weights were obtained for each sample: (1) weight after processing (pre-cleaned weight = W pre ); (2) weight after removing most remaining contaminants (partially cleaned weight = W par ); and (3) weight after removing all remaining contaminants (clean weight = W cln ). The regression of the actual number of mites on W cln was significant (P < 0.0001). Therefore, we evaluated the usefulness of W pre and W par as surrogates for W cln because they are easier to obtain. Concordance correlation coefficients (r c ) for W cln with both W pre and W par were < 0.80; therefore, correction factors for the two surrogates were calculated by dividing the average value of W cln by: (1) the average value of Wpre, or (2) the average value of W par . W pre and W par were adjusted by multiplying them by the appropriate factor. The r c values for corrected data were > 0.99. Our method lets us obtain an accurate estimate of the number of mites in 20-30 min, regardless of the number present, and is useful when the number of mites on a board > 4 500. Our method also avoids the loss of precision that occurs with sub-sampling. Varroa destructor / Apis mellifera / population estimation

-We examined the distribution of Varroa destructor on worker and queen brood in colonies of A. mellifera. With both worker and queen hosts present, the mite prevalence value for worker hosts was 75.0 ± 4.0% (lsmean ± SE), compared to 5.1 ± 4.0% for queen hosts (P < 0.0001). We also examined the response of mites to cuticular extracts of 5th instar worker and queen larvae using arrestment bioassays. In binary-choice tests at 0.5 larval equivalents (Leq), worker extract arrested 84.79 ± 4.98% of the mites, while queen extract arrested 15.21 ± 4.98% (P < 0.0001). At 0.8 Leq, worker extract arrested 89.75 ± 4.98%, while queen extract arrested 10.25 ± 4.98% (P < 0.0001). We also measured the repellent activity of royal jelly extract in a repellent bioassay. Royal jelly extract repelled 78.5 ± 2.6% of mites at 5 mg royal jelly equivalents (Rjeq); 85.6 ± 3.7% at 10 mg Rjeq; and 89.2 ± 3.8% at 20 mg Rjeq. The response at each dose was greater than the 10.5 ± 2.9% mites repelled by solvent controls (P < 0.0001). Our findings suggest that the low incidence of mites in queen brood is due, in part, to the repellent activity of royal jelly, and possibly to intrinsic differences between larval chemistries.Apis mellifera / Varroa jacobsoni / Varroa destructor / parasitic mite / royal jelly