We present 0 . 3 (band 6) and 1 . 5 (band 3) ALMA observations of the (sub)millimeter dust continuum emission for 25 radio galaxies at 1 < z < 5.2. Our survey reaches a rms flux density of ∼50 µJy in band 6 (200-250 GHz) and ∼20 µJy in band 3 (100-130 GHz). This is an order of magnitude deeper than single-dish 850 µm observations, and reaches fluxes where synchrotron and thermal dust emission are expected to be of the same order of magnitude. Combining our sensitive ALMA observations with low-resolution radio data from ATCA, higher resolution VLA data, and infrared photometry from Herschel and Spitzer, we have disentangled the synchrotron and thermal dust emission. We determine the star-formation rates and AGN infrared luminosities using our newly developed Multiresolution and multi-object/origin spectral energy distribution fitting code (Mr-Moose). We find that synchrotron emission contributes substantially at λ ∼1 mm. Through our sensitive flux limits and accounting for a contribution from synchrotron emission in the mm, we revise downward the median star-formation rate by a factor of seven compared to previous estimates based solely on Herschel and Spitzer data. The hosts of these radio-loud AGN appear predominantly below the main sequence of star-forming galaxies, indicating that the star formation in many of the host galaxies has been quenched. Future growth of the host galaxies without substantial black hole mass growth will be needed to bring these objects on the local relation between the supermassive black holes and their host galaxies. Given the mismatch in the timescales of any star formation that took place in the host galaxies and lifetime of the AGN, we hypothesize that a key role is played by star formation in depleting the gas before the action of the powerful radio jets quickly drives out the remaining gas. This positive feedback loop of efficient star formation rapidly consuming the gas coupled to the action of the radio jets in removing the residual gas is how massive galaxies are rapidly quenched.

Global food security is threatened by the effects of COVID-19 on international agricultural supply chains and locusts destroying crops and livelihoods in the Horn of Africa and South Asia. We quantify the possible impacts on global supplies and prices of wheat, rice and maize. We show that local production declines have moderate impacts on global prices and supply-but trade restrictions and precautionary purchases by a few key actors could create global food price spikes and severe local food shortages.Some major agricultural producing nations implemented export restrictions in the first half of 2020 1 , following market uncertainties triggered by the COVID-19 pandemic 2 . Several events compound COVID-19's disruption to supply chains, including locust infestations in the Horn of Africa and parts of the Middle East and South Asia 3 , shortages of farm labour 4,5 , a second wave of COVID-19 outbreaks and dry weather in Europe and South America 6,7 . COVID-19-related lockdowns can impact agriculture directly (mainly through restrictions to farm labour, which is one factor that can reduce yields), meaning that regions with high employment in agriculture may experience the largest losses in crop production. For example, the Ebola outbreak in West Africa in 2014 reduced labour availability for farming and led to a 20% decline in rice production 8 during the outbreak, with large economic impacts in the following year 9 .We quantified the impact of these various threats to the world supplies and prices of wheat, maize and rice. These crops form the backbone of global trade in staple crops, with high importance for food security; they comprise 43% of calories and 37% of protein directly consumed by the human population 10 . To determine the supply chain impacts of the COVID-19 pandemic and other threats to these key crops, we combined an analysis of impaired supply with a global agricultural commodity price model 11 including trade policies and storage. To quantify the impacts of crop failures, we developed scenarios that included a 1-in-5-year production decline due to drought and lockdown effects in three major exporting countries and a 1-in-20-year decline in production in the countries most threatened by the locust infestations as of May 2020. We compared these scenarios to a baseline scenario based on the joint Organisation for Economic Co-operation Development (OECD) and Food and Agriculture Organization (FAO) supply and demand forecasts for 2020/21, which do not factor in these production shortfalls.Global stock-to-use ratios of rice, wheat and maize are at historically high levels (Supplementary Fig. 1). This situation is in