If you have any questions, please contact your Hackathon Lead, Shannon Tafadzwa Sikadi - Shannon_Sikadi.

Maize is Zimbabwe’s most important staple crop, feeding millions and driving rural livelihoods. But yields are increasingly threatened by fungal leaf diseases like Common Rust, Gray Leaf Spot, and Blight—affecting farms across both humid and dry regions, from Manicaland to Masvingo.

Smallholder farmers, who grow most of the country’s maize, often lack tools for early disease detection. Current diagnosis methods rely on manual inspection, which is slow, inconsistent, and hard to scale. As a result, diseases often go untreated until it’s too late, causing serious yield losses, food insecurity, and financial strain.

This challenge invites you to build an AI-powered image classification model that can accurately identify maize leaf diseases. Your model should classify images into one of four categories:

• Common Rust
• Gray Leaf Spot
• Blight
• Healthy

The model must be accurate, fast, and robust under real-world conditions—working across varying lighting, angles, and image quality. Ideally, it should be lightweight enough to run offline or on mobile devices, enabling practical use in remote farming areas.

By developing such a tool, you're not just solving a technical challenge—you’re helping bring precision agriculture to smallholders across Zimbabwe and sub-Saharan Africa.

Deep Learning IndabaX Zimbabwe

Deep Learning IndabaX Zimbabwe is the country’s leading platform for AI and machine learning collaboration, bringing together researchers, developers, and industry leaders. As part of the global Deep Learning Indaba movement, it focuses on applying AI responsibly to solve local challenges, drive innovation, and support economic growth. IndabaX Zimbabwe empowers the next generation of AI talent and fosters ethical, impactful solutions tailored to Zimbabwe’s context.

About GDG Harare

Google Developer Groups (GDGs) are vibrant, local communities of developers passionate about Google technologies.GDG Harare is a chapter of Google Developer Groups and is part of a global network of developers, fostering collaboration and innovation within the Google ecosystem. Organized by volunteers, GDG Harare offers a platform for developers to connect, learn, and share their expertise. We host regular events, workshops, and hackathons, providing opportunities for hands-on learning and networking.

The error metric for this challenge is Log Loss.

Note the ID does not contain a suffix such as jpg or JPG.

Your submission file could look something like this:

ID            Blight  Common_Rust  Gray_Leaf_Spot  Healthy

image_000001  0.11    0.95         0.23            0.40

First Prize: $250 USD

Second Prize: $150 USD

Third Prize: $100 USD

There are 500 Zindi points available. You can read more about Zindi points here.

🚀 What to know to get started with Zindi Challenges

How to enroll in your first Zindi competition

How to create a team on Zindi

How to use Colab on Zindi

How to mount a drive on Colab

If you have any questions, please contact your Hackathon Lead, Shannon Tafadzwa Sikadi - Shannon_Sikadi.

• Languages and tools: You may only use open-source languages and tools in building models for this challenge.
• Who can compete: The hackathon is open to IndabaX Zimbabwe Community members.
• Submission Limits: 10 submissions per day, 70 submissions overall.
• Team size: Max team size of 3
• Public-Private Split: Zindi maintains a public leaderboard and a private leaderboard for each challenge. The Public Leaderboard includes approximately 30% of the test dataset. The private leaderboard will be revealed at the close of the challenge and contains the remaining 70% of the test set.
• Data Sharing: CC-BY SA 4.0 license
• Code Review: Top 5 on the private leaderboard will receive an email requesting their code at the close of the challenge. You will have 1 hour to submit your code.
• Code sharing: Multiple accounts, or sharing of code and information across accounts not in teams, is not allowed and will lead to disqualification.
• Solutions of value: Solutions handed over to clients must be of value to the client, regardless of leaderboard ranking.

ENTRY INTO THIS CHALLENGE CONSTITUTES YOUR ACCEPTANCE OF THESE OFFICIAL CHALLENGE RULES.

Full Challenge Rules

The hackathon is open to IndabaX Zimbabwe Community members.

Teams and collaboration

You may participate in challenges as an individual or in a team of up to three people. When creating a team, the team must have a total submission count less than or equal to the maximum allowable submissions as of the formation date. A team will be allowed the maximum number of submissions for the challenge, minus the total number of submissions among team members at team formation. Prizes are transferred only to the individual players or to the team leader.

Multiple accounts per user are not permitted, and neither is collaboration or membership across multiple teams. Individuals and their submissions originating from multiple accounts will be immediately disqualified from the platform.

Code must not be shared privately outside of a team. Any code that is shared, must be made available to all challenge participants through the platform. (i.e. on the discussion boards).

The Zindi data scientist who sets up a team is the default Team Leader but they can transfer leadership to another data scientist on the team. The Team Leader can invite other data scientists to their team. Invited data scientists can accept or reject invitations. Until a second data scientist accepts an invitation to join a team, the data scientist who initiated a team remains an individual on the leaderboard. No additional members may be added to teams within the final 5 days of the challenge or last hour of a hackathon.

The team leader can initiate a merge with another team. Only the team leader of the second team can accept the invite. The default team leader is the leader from the team who initiated the invite. Teams can only merge if the total number of members is less than or equal to the maximum team size of the challenge.

A team can be disbanded if it has not yet made a submission. Once a submission is made individual members cannot leave the team.

All members in the team receive points associated with their ranking in the challenge and there is no split or division of the points between team members.

Datasets, packages and general principles

The solution must use publicly-available, open-source packages only.

You may use only the datasets provided for this challenge.

You may use pretrained models as long as they are openly available to everyone.

Automated machine learning tools such as automl are not permitted.

If the error metric requires probabilities to be submitted, do not set thresholds (or round your probabilities) to improve your place on the leaderboard. In order to ensure that the client receives the best solution Zindi will need the raw probabilities. This will allow the clients to set thresholds to their own needs.

You are allowed to access, use and share challenge data for any commercial, non-commercial, research or education purposes, under a CC-BY SA 4.0 license.

You must notify Zindi immediately upon learning of any unauthorised transmission of or unauthorised access to the challenge data, and work with Zindi to rectify any unauthorised transmission or access.

Your solution must not infringe the rights of any third party and you must be legally entitled to assign ownership of all rights of copyright in and to the winning solution code to Zindi.

Submissions and winning

You may make a maximum of 10 submissions per day.

You may make a maximum of 70 submissions for this challenge.

Before the end of the challenge you need to choose 2 submissions to be judged on for the private leaderboard. If you do not make a selection your 2 best public leaderboard submissions will be used to score on the private leaderboard.

During the challenge, your best public score will be displayed regardless of the submissions you have selected. When the challenge closes your best private score out of the 2 selected submissions will be displayed.

Zindi maintains a public leaderboard and a private leaderboard for each challenge. The Public Leaderboard includes approximately 30% of the test dataset. While the challenge is open, the Public Leaderboard will rank the submitted solutions by the accuracy score they achieve. Upon close of the challenge, the Private Leaderboard, which covers the other 70% of the test dataset, will be made public and will constitute the final ranking for the challenge.

Note that to count, your submission must first pass processing. If your submission fails during the processing step, it will not be counted and not receive a score; nor will it count against your daily submission limit. If you encounter problems with your submission file, your best course of action is to ask for advice on the challenge page.

If you are in the top 10 at the time the leaderboard closes, we will email you to request your code. On receipt of email, you will have 48 hours to respond and submit your code following the Reproducibility of submitted code guidelines detailed below. Failure to respond will result in disqualification.

If your solution places 1st, 2nd, or 3rd on the final leaderboard, you will be required to submit your winning solution code to us for verification, and you thereby agree to assign all worldwide rights of copyright in and to such winning solution to Zindi.

If two solutions earn identical scores on the leaderboard, the tiebreaker will be the date and time in which the submission was made (the earlier solution will win).

The winners will be paid via bank transfer, PayPal if payment is less than or equivalent to $100, or other international money transfer platform. International transfer fees will be deducted from the total prize amount, unless the prize money is under $500, in which case the international transfer fees will be covered by Zindi. In all cases, the winners are responsible for any other fees applied by their own bank or other institution for receiving the prize money. All taxes imposed on prizes are the sole responsibility of the winners. The top winners or team leaders will be required to present Zindi with proof of identification, proof of residence and a letter from your bank confirming your banking details. Winners will be paid in USD or the currency of the challenge. If your account cannot receive US Dollars or the currency of the challenge then your bank will need to provide proof of this and Zindi will try to accommodate this.

Please note that due to the ongoing Russia-Ukraine conflict, we are not currently able to make prize payments to winners located in Russia. We apologise for any inconvenience that may cause, and will handle any issues that arise on a case-by-case basis.

Payment will be made after code review and sealing the leaderboard.

You acknowledge and agree that Zindi may, without any obligation to do so, remove or disqualify an individual, team, or account if Zindi believes that such individual, team, or account is in violation of these rules. Entry into this challenge constitutes your acceptance of these official challenge rules.

Zindi is committed to providing solutions of value to our clients and partners. To this end, we reserve the right to disqualify your submission on the grounds of usability or value. This includes but is not limited to the use of data leaks or any other practices that we deem to compromise the inherent value of your solution.

Zindi also reserves the right to disqualify you and/or your submissions from any challenge if we believe that you violated the rules or violated the spirit of the challenge or the platform in any other way. The disqualifications are irrespective of your position on the leaderboard and completely at the discretion of Zindi.

Please refer to the FAQs and Terms of Use for additional rules that may apply to this challenge. We reserve the right to update these rules at any time.

Reproducibility of submitted code

If your submitted code does not reproduce your score on the leaderboard, we reserve the right to adjust your rank to the score generated by the code you submitted.

If your code does not run you will be dropped from the top 10. Please make sure your code runs before submitting your solution.

Always set the seed. Rerunning your model should always place you at the same position on the leaderboard. When running your solution, if randomness shifts you down the leaderboard we reserve the right to adjust your rank to the closest score that your submission reproduces.

Custom packages in your submission notebook will not be accepted.

You may only use tools available to everyone i.e. no paid services or free trials that require a credit card.

Read this article on how to prepare your documentation and this article on how to ensure a successful code review.

Consequences of breaking any rules of the challenge or submission guidelines:

• First offence: No prizes for 6 months and 2000 points will be removed from your profile (probation period). If you are caught cheating, all individuals involved in cheating will be disqualified from the challenge(s) you were caught in and you will be disqualified from winning any challenges for the next six months and 2000 points will be removed from your profile. If you have less than 2000 points to your profile your points will be set to 0.
• Second offence: Banned from the platform. If you are caught for a second time your Zindi account will be disabled and you will be disqualified from winning any challenges or Zindi points using any other account.

Teams with individuals who are caught cheating will not be eligible to win prizes or points in the challenge in which the cheating occurred, regardless of the individuals’ knowledge of or participation in the offence.

Teams with individuals who have previously committed an offence will not be eligible for any prizes for any challenges during the 6-month probation period.

Monitoring of submissions

• We will review the top 10 solutions of every challenge when the challenge ends.
• We reserve the right to request code from any user at any time during a challenge. You will have 24 hours to submit your code following the rules for code review (see above). Zindi reserves the right not to explain our reasons for requesting code. If you do not submit your code within 24 hours you will be disqualified from winning any challenges or Zindi points for the next six months. If you fall under suspicion again and your code is requested and you fail to submit your code within 24 hours, your Zindi account will be disabled and you will be disqualified from winning any challenges or Zindi points with any other account.