Pls I went to my farm and saw this.
Is it a Fungi disease pls

This ur camera seff...but Looks like chlorosis to me...

.common with soil deficient of iron...ur plant isn't producing chlorophyll well...which means reduced photosynthesis....long story short...it not good...

But it's no biggie though...get a good fertilizer with iron and other nutrients like NPK...

Thanks bro.
More answers pls

I found this link four u. Check it out:
https://www.gardeningknowhow.com/edible/fruits/watermelon/yellow-brown-watermelon-leaves.htm

This is interesting. Is it really chlorosis? I will appreciate contrary opinion to my view, or any comment. Let us learn together. Yes, I agree, the picture quality is terrible. But we know how farming is. Might be, the guy had to go with a less quality phone since we are in rainy season. Rain destroys good phones on farm. Lol.

Chlorosis
Derived from the prefix Chloro.
Chlorophyll, Chlorosis...lol. it simply means green.

Chlorosis is when leaves are yellow. Which nutrient is responsible for that green color? It is Nitrogen. Lack of nitrogen. Newbie's immediate thought might be to provide more nitrogen via NPK. Hmmmm! That may not be the case. In fact, you may provide more and it may get worse.

Anyway, I like the recommendation of the poster above me; however, I would not just apply any fertilizer. You need to understand what can cause chlorosis. It is not only iron deficiency. It can be any other nutrient apart from potassium and some other micro nutrients. There is iron chlorosis, magnesium chlorosis, even lack of phophorus and too much of it can cause it.

But really is there anything like too much nutrient on Nigerian micro scale farms? Lol. From experience, it is very unlikely. So, I will not pay attention too much to this since I know most farmers do not apply enough nutrients. In fact, they depend more on natural nutrients in the soil.

Bad roots cannot produce good leaves. I might pull out some plants to check how robust the roots are. If the roots are fragile or tiny, phophorus based fertilizer will help. If the roots are ok, I would order for fast application of micro nutrients first. Enough micro nutrients via foliar application. Application will not be via roots as there might still be issues with the roots. Then, I would quickly bring in my instrument to check the following: soil ph, nitrogen in the soil. You must be ready to compare these two readings from all parts of the farm, and then use visual troubleshooting to understand what is going on. PH affects nutrients up take too.

I believe I have given a quick troubleshooting technique. But do I really agree this is chlorosis? No, no, and a big No. Why?

Watermelon leaves picture OP posted have yellow spots. And OP's heading says it all: "yellow spots on my watermelon..." Chlorosis is not likely to show yellow spots. It is always faint green or bright yellow on most parts of the leaves without spots. Just unfortunate the picture quality is terrible and we cannot see it very well. I always go to farms with excellent phones. Infact, there are so many phone apps which farmers need. Apps which aid excellent set up, easy troubleshooting, and excellent picture editing.

So, what is my take? It is likely a fungi disease just like what OP had initially thought. OP, your disease management or nutritional management might be poor. It is why I address nutrition while fighting or preventing diseases. Your plants might have very low immume system.

Again, most likely you chose a terrible variety for your farm location which cannot fight specific common diseases in your area. No matter how hard you fight such diseases, you might likely lose the battle.

What do I think is wrong? Most likely downy mildew. If you are in south west, south south, or south east, it is likely your plants are infected with downy mildew.

Downy Mildew
There are mainly 2 types of mildews. Powdery mildew, and downy mildew. Just like the name sounds, powdery mildew leaves powdery look on the leaves, while downey leaves yellow spots. Both mildews destroy plants rapidly. They are serious infections which have rendered many farms useless.

How to address mildews.
1. Always make sure your farm soil is with high organic matters. Use compost.
2. Feed very well. Check ph before planting, anyway, if you use enough manure, you may not worry about ph. I guess OP did not use manure at all or very little. Compost/manure solves many soil challenges. Personally, I do not use manure or compost as source of nurrients. I use them to fight diseases, make soil better, and correct ph because of the huge organic matters there. I count the nutrients there insignificant. If you want to know how insignificant nutrients in manure are, just go to a less fertile land and try to cultivate cucumber or watermelon. By the time you have wasted your energy and money on huge manure, you will understand better. If you are lucky, and you have someone who tells you to help yourself with little NPK, you are extremely lucky. Anyway, die hard organic guys can disagree. As long as they have the zeal, strength and cash to move huge loads of manure or compost to farm, it is ok. In fact, if I can employ one of them to use such zeal on my farms, i will. A way out is having livestock on your farm. Not Very easy way since we all want to reduce start up costs on farms. Poultry, piggery, fishery, etc. Rabbit manure is a compost already. It is just excellent. Its urine and poo can be used. And using worms to make compost is excellent too. Just feed your worms with fresh manure. Hmmmm. Just that it is too much energy to do. Proper planning is necessary.
3. Spray both systemic and contact fungicides. Also, you may need to drench some kind of fungicides at this stage to help your plants fight a good fight.
4. If you have a variety with low resistant to mildew, you are likely to lose the fight.

I hope you can get this done. I hope this is a pilot and not large scale production.

Best of luck.

Thanks so much.
This is a better picture of the plant.

I applied Z-force Mancozeb 80WP.

Tolumhen:
I applied Z-force Mancozeb 80WP.

The new picture clearly shows it is downy mildew.

You applied mancozeb only during rainy season? Na on top your plants leaves downy mildew have been dancing Azonto. They will soon start Shaku Shaku. I do not know how terrible the case is but it may be waste of resources and energy to treat at a certain stage.

You actually went for the cheapest fungicide, and you used it repeatedly over a long period of time. And it does not even work because I am sure you did not add a sticker to it which make it stay on the leaves even after it rains.

Fungicides are very expensive. It is not just spraying anything. You need to understand what you are doing. Get enough fungicides before embarking on a farm. Spending N100,000 on only different brands of fungicides is not a bad investment. You will use them over a long period of time. And you will surely see the benefits. There are some other nutrients that are just 100ml that cost as much as over N10,000.

However, one can still go on a low cost spraying formular effectively. I cannot just start recommending what to use without seeing what is on ground. It is like a doctor writing prescription without checking the patient. When cancer reach a stage, they tell the person to go make peace with God and enjoy his final moments with pain relieving pills.

Contact me privately. I will assist you. I will check the rate of infection and see if it can be treated. I will make recommendation and I might even send you some nutrients. Be rest assured that everything I send to you will be free. I know you are under tension, and asking you to buy extremely expensive brands can kill your fighting spirit.

The only condition is that you must post updates and pictures of your farm here and report till the end. I will give you the report template you must use. Just make sure you follow them. And lastly, I do not write out brand names on public forum. We can write active ingredient but not brand names. I am not here to promote any seller or importer.

I have about 800 stands.
And there are about 12 infected stands.
The infection has reduced somehow.
They're just 4 weeks old.
This is the 2nd time I'll be cultivating watermelon � so I'm not ignorant of the fact that Mancozeb is cheap and it's a protective Fungicide..

Alright bro.
Can I contact you on WhatsApp?

I'm a 400L student of Funaab.

How can I control apphids pls.
Can cypermethrin control them

Visit your watermelon farm everyday and spray fungicides top and bottom of every leaves.

Aphids are insects..
They're under the leaves.

Use fighter 35 Ec and you would be just fine. Spray it every wk or 2wks....

Tolumhen:
Aphids are insects..
They're under the leaves.

Thanks Bro.

I'll post pictures of the farm here steady.

Bro pls where can I get it and how much is it.
I live in Funaab
And please can you suggest any good systemic Fungicide thanks

Nairaland user prescribes a brand on this forum and boom, off to market to buy. You did not even bother to check what exactly the product does, if it is what is really needed, or if it a product which needs extra care. This is why I do not write about chemicals on public forums. Wrong usage of chemicals is top on the ladder of reasons farmers fail. Or when your workers do not carry your instructions rightly. It is why you must supervise spraying and nutrient application very well.

Land preparation, Staking, harvesting can be done without you. But using agro- chemicals and nutrients rightly is a top priority on farm. Some just pay one guy N2,000 to spray. A dey laugh. Some jump in and jump out spraying same chemical weekly, a dey cry for such plants. Lol.

There are systemic chemicals you spray and the effect stays in the plants' system for more than 6 weeks. A manufacturer might produce 40% of the chemical per liter of this chemical under a brand name X. Then another manufacturer comes with its brand Y using 40% +/-15 of the same chemical and combine it with another chemical which quickly leaves the system of plants in 48 hours. While it is permitted to use that which goes off after 48 hours every week, you cannot use the one which stays on plants for 6 weeks every week. This is what I regard as the highest abuse and wreckless way of using chemicals.

To use chemicals well, and to be able to safe guard the health of consumers, you must buy different kinds. Some brands combine chemicals, and some products are single ingredient. Again, you must know the right percentage of chemical in every liter of liquid.

This is how one farmer who claimed to be organic greenhouse farmer deceived her consumers. When those crazy pests like the one OP mentioned here was troubling her plants inside her greenhouse, and she could not find any solution, she resolved to using the same chemical prescribed like this on nairaland every week till it got to a point the pests developed resistant to the chemical and it worked no more. And she kept pretending she is doing organic farming just because she used odorless chemical. The people who eat such products are in serious danger.

I have missed it many times too, but I learn daily and move on. I have learned never to give out some vital information until I know the person is responsible. While I disguise some seeds for some farmers, I sent a seed undisguised to one of my partners yesterday because I trust him. This is a variety I am working one and I want to get the license to produce locally too. And this person knows about it. I trust him well.

I do not know how to say it. What separates a good farmer from a terrible one is having sound basic knowledge of nutritional, pest & diseases management. The ability to make thorough research on the internet. Most people just search for how to grow watermelon on the internet. Is that the only topic you should search for? When there are so many challenges you can tackle using the internet. But you will not know how to tackle them if you are not ready to do very little science.

You know a terrible mind easily when you hear the phrase "internet farmers are bad". Lol. How can you be a great farmer if you arent an internet farmer? What they should label those crazy consultant is "rank xerox farmers, photocopy farmers, copy and paste farmers, etc".

What is the content of this agrochemical I want to use?
Do I need just one chemical? Or combinations?
When should I use it?
Are there alternatives?
How many days interval is recommended?
Maybe I can add an organic or safe nutrient which will prolong its effect after it has been washed away from the sysyem of the plants?
Which other chemicals I must not mix with this chemical?
Which chemicals I must not use at X days before or after using it?
.....and many more.

I train people. I am not interested in your ability to live rural life to farm. Nope. I am not interested in your ability to checkmate workers and make sure they wake up 7am and close at 7pm daily. I am not interested that you join workers to do rigorous job to make it faster. I am interested in just 3 things. That you are able to listen, and you can visualize with your mind, and trustworthy. Those are the qualities I need. So, when you bring PhD AgroNonsense certificate to my table and you do not have these three qualities, we cannot work together. When you read on the internet, you listen very well by medidating deeply.

25 students finished my training, and I spotted just one guy who listens well, and visualises with his mind. Just yesterday, I asked him for help check a chemical out. He did not stop in sending the dosage, but went deeper to give alternatives. I was like...this is my kind of person. Very detailed. I do not mind getting him investors who will spend some millions on his farm if he meets the third quality which is trust. While there is a masters holder somewhere who has been talking to me saying...I am an expert, we do analysis in school, i must do organic, bla bla bla. Recently, I heard " i am quitting Agric". Sorry. Lol! Where are the certificate guys today? And I wanted to really assist this masters degree holder. I really wanted to.

Why just spray MMForce, XYForce, NairalandForce, AgriculturalSectionForce, DuduForce, YellowForce, StupidForce, IdiotForce, IlliterateForce, KillConsumersForce, WicknessForce, etc unnecessarily.

I have told you. Get in touch with me through the right channel. Write me the way you can write all nairaland members sir and I will respond latest after 48 hours. It will not even be up to that because I check my email every morning.

I wrote a detailed post here just because you said you are in an Agricultural university - Federal University of Agricultural....bla bla bla (FUNAAD or FUNAAB or whatever).

I advise you to sit down and learn active ingredients. Read, read, read. No farmer excels by asking Agricultural experts recommendations. Are the so called Agric experts the ones facing the challenges? Where are our rank xerox farmers. New pests come out everytime. Where are the DDForce farmers? Do you realise Mancozeb that has just failed you was just enough in those days to fight fungi diseases? What of today? Where are the mancozeb farmers?

In conclusion, I will teach you some few things which you can develop on.

But I made up my mind, if there is any farm owner who is ready to be a strategist on farm (not to become a supervisor, but to solve problems. Requirement is readiness to make research at your free time), just write me. Just a farm owner who has got cash because you will be importing samples of Agricultural nutrients (you need to apply for certifucates, licenses through Ministry of Agric) to get most. I do not see anyone who is not financially capable doing this well. But if you have the means, you have a small backyard, or you can turn a room in your home into a laboratory using gro light, humidity corrector, etc. Interested in tissue culture and set your place, and you have got the cash, hook up with me. I do not need to meet you, i will just direct your path. This is a paid training. Not free. I will divulge 100% of my head into you. And you will have access to me. I will hook you up with many people too. Maybe after 4 years, you will be the one I will have to run after to kindly help me cos I do not know about the subject. However, be ready to pay. This is me going into you.

OP, get in touch and I will give you basic tips you can develop on if you have a mind you can use to think. Im not collecting a kobo from you.

Please, read through my thread:
https://www.nairaland.com/4422247/using-micro-scale-agricultural-systems

Best of luck!

fluentinfor:
Nairaland user prescribes a brand on this forum and boom, off to market to buy. You did not even bother to check what exactly the product does, if it is what is really needed, or if it a product which needs extra care. This is why I do not write about chemicals on public forums. Wrong usage of chemicals is top on the ladder of reasons farmers fail. Or when your workers do not carry your instructions rightly. It is why you must supervise spraying and nutrient application very well.

Land preparation, Staking, harvesting can be done without you. But using agro- chemicals and nutrients rightly is a top priority on farm. Some just pay one guy N2,000 to spray. A dey laugh. Some jump in and jump out spraying same chemical weekly, a dey cry for such plants. Lol.

There are systemic chemicals you spray and the effect stays in the plants' system for more than 6 weeks. A manufacturer might produce 40% of the chemical per liter of this chemical under a brand name X. Then another manufacturer comes with its brand Y using 40% +/-15 of the same chemical and combine it with another chemical which quickly leaves the system of plants in 48 hours. While it is permitted to use that which goes off after 48 hours every week, you cannot use the one which stays on plants for 6 weeks every week. This is what I regard as the highest abuse and wreckless way of using chemicals.

To use chemicals well, and to be able to safe guard the health of consumers, you must buy different kinds. Some brands combine chemicals, and some products are single ingredient. Again, you must know the right percentage of chemical in every liter of liquid.

This is how one farmer who claimed to be organic greenhouse farmer deceived her consumers. When those crazy pests like the one OP mentioned here was troubling her plants inside her greenhouse, and she could not find any solution, she resolved to using the same chemical prescribed like this on nairaland every week till it got to a point the pests developed resistant to the chemical and it worked no more. And she kept pretending she is doing organic farming just because she used odorless chemical. The people who eat such products are in serious danger.

I have missed it many times too, but I learn daily and move on. I have learned never to give out some vital infirmation until I know the person is responsible. While I disguise some seeds for some farmers, I sent a seed undisguised to one of my partners yesterday because I trust him. This is a variety I am working one and I want to get the license to produce locally too. And this perdon knows about it. I trust him well.

I do not know how to say it. What separates a good farmer from a terrible one is having sound basic knowledge of nutritional, pest & diseases management. The ability to make thorough research on the internet. Most people just search for how to grow watermelon on the internet. Is that the only topic you should search for? When there are so many challenges you can tackle using the internet. But you will not know how to tackle them if you are not ready to do very little science.

You know a terrible mind easily when you hear the phrase "internet farmers are bad". Lol. How can you be a great farmer if you arent an internet farmer? What they should label those crazy consultant is "rank xerox farmers, photocopy farmers, copy and paste farmers, etc".

What is the content of this agrochemical I want to use?
Do I need just one chemical? Or combinations?
When should I use it?
Are there alternatives?
How many days interval is recommended?
Maybe I can add an organic or safe nutrient which will prolong its effect after it has been washed away from the sysyem of the plants?
Which other chemicals I must not mix with this chemical?
Which chemicals I must not use at X days before or after using it?
.....and many more.

I train people. I am not interested in your ability to live rural life to farm. Nope. I am not interested in your ability to checkmate workers and make sure they wake up 7am and close at 7pm daily. I am not interested that you join workers to do rigorous job to make it faster. I am interested in just 3 things. That you are able to listen, and you can visualize with your mind, and trustworthy. Those are the qualities I need. So, when you bring PhD AgroNonsense certificate to my table and you do not have these three qualities, we cannot work together. When you read on the internet, you listen very well by medidating deeply.

25 students finished my training, and I spotted just one guy who listens well, and visualises with his mind. Just yesterday, I asked him for help check a chemical out. He did not stop in sending the dosage, but went deeper to give alternatives. I was like...this is my kind of person. Very detailed. I do not mind getting him investors who will spend some millions on his farm if he meets the third quality which is trust. While there is a masters holder somewhere who has been talking to me saying...I am an expert, we do analysis in school, i must do organic, bla bla bla. Recently, I heard " i am quitting Agric". Sorry. Lol! Where are the certificate guys today? And I wanted to really assist this masters degree holder. I really wanted to.

Why just spray MMForce, XYForce, NairalandForce, AgriculturalSectionForce, DuduForce, YellowForce, StupidForce, IdiotForce, IlliterateForce, KillConsumersForce, WicknessForce, etc unnecessarily.

I have told you. Get in touch with me through the right channel. Write me the way you can write all nairaland members sir and I will respond latest after 48 hours. It will not even be up to that because I check my email every morning.

I wrote a detailed post here just because you said you are in an Agricultural university - Federal University of Agricultural....bla bla bla (FUNAAD or FUNAAB or whatever).

I advise you to sit down and learn active ingredients. Read, read, read. No farmer excels by asking Agricultural experts recommendations. Are the so called Agric experts the ones facing the challenges? Where are our rank xerox farmers. New pests come out everytime. Where are the DDForce farmers? Do you realise Mancozeb that has just failed you was just enough in those days to fight fungi diseases? What of today? Where are the mancozeb farmers?

In conclusion, I will teach you some few things which you can develop on.

But I made up my mind, if there is any farm owner who is ready to be a strategist on farm (not to become a supervisor, but to solve problems. Requirement is readiness to make research at your free time), just write me. Just a farm owner who has got cash because you will be importing samples of Agricultural nutrients (you need to apply for certifucates, licenses through Ministry of Agric) to get most. I do not see anyone who is not financially capable doing this well. But if you have the means, you have a small backyard, or you can turn a room in your home into a laboratory using gro light, humidity corrector, etc. Interested in tissue culture and set your place, and you have got the cash, hook up with me. I do not need to meet you, i will just direct your path. This is a paid training. Not free. I will divulge 100% of my head into you. And you will have access to me. I will hook you up with many people too. Maybe after 4 years, you will be the one I will have to run after to kindly help me cos I do not know about the subject. However, be ready to pay. This is me going into you.

OP, get in touch and I will give you basic tips you can develop on if you have a mind you can use to think. Im not collecting a kobo from you.

Please, read through my thread:
https://www.nairaland.com/4422247/using-micro-scale-agricultural-systems

Best of luck!

pls sir how does the training works and what demands or requirements do one need to mentor under you sir

What's the wahala self?
You're making Farming look like Rocket Science uncle �.
I asked a question and he suggested something.
And now you're telling me I didn't bother to check yen yen yen.
Just make a suggestion. I'll read about it..
Don't come here and start disapproving every damn thing jare.

aka12:
pls sir how does the training works and what demands or requirements do one need to mentor under you sir

1. Learn 5 veggies.
Buy all materials by yourself, and use your backyard to practise. It is free. Make inquiry when next I will do it. Not available now. Always in group to share cost of purchasing materials.

2. Strategic Veggie Farming:
Very deep research. Nutritional Management, Pests & Diseases Management. Not Free.
Grafting Optional (You meet me here)
Tissue Culture Optional (You meet me here too)

3. Investors Option:
Micro- Scale Agric-business
Learn how to read financial plans, learn how to pull out information from farmers, learn how to spot good deals. Learn how to put figures together to make a good decision.

Demands: Buy materials by yourself. Some are in 25kg bags and might cost as much as N15k to N35k, yet you may need just 1kg for what you are doing. And you may buy like 6 kinds. Maybe it will encourage you to use them on farm later. You may import materials which are not available here. You will grow microoganisms too.

Requirements: A mind which can see, two ears which listen attentively, and the ability to be trust- worthy. I am not impressed or moved with certificates and diplomas.

Tolumhen:
What's the wahala self?
You're making Farming look like Rocket Science uncle �.
I asked a question and he suggested something.
And now you're telling me I didn't bother to check yen yen yen.
Just make a suggestion. I'll read about it..
Don't come here and start disapproving every damn thing jare.

Ok sir. I agree with you, farming is not rocket science and you can always check it up. You have a recommendation above. You should go check it sir. It is available in shops. Please kindly drop updates of your garden here and let us know how well the things you checked up work well.
All the best.