Ghana Maize Disease Detection System - offline-capable app for smallholder farmers. MobileNetV2 transfer learning + TFLite + React Native.
# Offline-Capable Maize Disease Detection System
A deep learning-powered mobile application for the early detection of maize
diseases, designed specifically for smallholder farmers in Ghana's northern
sector. The system runs **fully offline** on low-cost Android devices (2 GB
RAM, Android 6.0+), making it accessible to farmers who lack reliable
internet connectivity.
This project is the artefact of a final-year project report at C. K. Tedam
University of Technology and Applied Sciences. It uses MobileNetV2 transfer
learning, converts the trained model to a lightweight TensorFlow Lite file,
and embeds it in a React Native app with English and Twi language support.
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## Background & Motivation
Maize (*Zea mays*) is Ghana's most important cereal crop and the primary
staple food for over 31 million Ghanaians. Smallholder farmers in the
northern sector — particularly the Upper East Region — rely heavily on maize
for food security and household income. However, they face severe challenges
in disease management:
- Ghana's **extension officer-to-farmer ratio** is about **1:1,500**, three
times worse than the recommended 1:500. Rural farmers have minimal access
to expert diagnosis.
- Visual symptoms often appear only after a disease has progressed, and
maize disease outbreaks can cause **yield losses of 30–80%**.
- Most smallholder farmers cannot distinguish between diseases with similar
symptoms, leading to incorrect or absent treatment.
- Most existing mobile disease-detection apps **require internet access**,
which is unreliable in rural northern Ghana.
- Most models are trained only on laboratory images and **foreign disease
sets**, and do not cover African diseases such as **Maize Streak Virus
(MSV)** and **Maize Lethal Necrosis (MLN)**, nor provide local-language
support or a rejection class for non-maize images.
This system addresses these gaps by providing an accurate, lightweight,
fully offline tool with English/Twi support, a `Not_Maize` rejection class,
a …