In most of the developing countries, the economy is largely based on agriculture. The poor availability of skilled personnel and of appropriate supporting infrastructure, make crop fields vulnerable to the outbreak of plant diseases, possibly due to spreading viruses and fungi, or to adverse environmental conditions, such as drought. The mobile application PlantVillage Nuru provides an invaluable tool for early detection of plant diseases and sustainable food production. A mobile device endowed with Nuru is a powerful mobile sensor: it analyzes plant images and uses an AI engine to recognize health issues. In this article, we propose a crowdsensing framework, where Nuru is adopted at large scale in the farmer population. We tackle the device deployment problem, where device mobility is only partially controllable, mostly in an indirect manner, through incentives. We propose two problem formulations, and related algorithms, to minimize the number of required smartphones while providing sufficient geographical coverage. We study the proposed models in simulated as well as real scenarios, showing that they outperform the current solutions in terms of monitoring accuracy and completeness, with lower cost. Then, we describe the testbed implementation, confirming the applicability of the proposed crowdsensing framework in a real scenario in Kenya.

East Africa is experiencing the worst locust infestation in over 25 years, which has severely threatened the food security of millions of people across the region. The primary strategy adopted by human experts at the United Nations Food and Agricultural Organization (UN-FAO) to tackle locust outbreaks involves manually surveying at-risk geographical areas, followed by allocating and spraying pesticides in affected regions. In order to augment and assist human experts at the UN-FAO in this task, we utilize crowdsourced reports of locust observations collected by PlantVillage (the world's leading knowledge delivery system for East African farmers) and develop PLAN, a Machine Learning (ML) algorithm for forecasting future migration patterns of locusts at high spatial and temporal resolution across East Africa. PLAN's novel spatio-temporal deep learning architecture enables representing PlantVillage's crowdsourced locust observation data using novel image-based feature representations, and its design is informed by several unique insights about this problem domain. Experimental results show that PLAN achieves superior predictive performance against several baseline models - it achieves an AUC score of 0.9 when used with a data augmentation method. PLAN represents a first step in using deep learning to assist and augment human expertise at PlantVillage (and UN-FAO) in locust prediction, and its real-world usability is currently being evaluated by domain experts (including a potential idea to use the heatmaps created by PLAN in a Kenyan TV show). The source code is available at https://github.com/maryam-tabar/PLAN.

Fall armyworm (FAW) is a polyphagus pest with a preference for young maize leaves that relocates to the cob during cob development and can devastate maize yields. Time series anomaly change detection and first derivative growth pattern analyses were conducted under the hypothesis that, if unimpeded and occurring during the vegetativegrowth stage, FAW presence will result in a reduction of the LAI or total green biomass (NDVI) of the crop. We have conducted observations NDVI/LAI at three different scales from continental to field scales., (i) Sentinel-2 a+b and (ii) micro-satellite Planet Scope, (iii) multispectral camera. Correlations between LAI and (i) NDVI of (i, ii, iii) were R2 0.60, 0.66 and 0.35, respectively. The NDVI time series and first derivative were then compared to the FAW damage recorded using a mobile app.