I’m looking for imprecise, cheap insect control options. I found a neem leaf spray and cooking oil spray. Does anyone have experience with these? Do they affect the flavor of the crop (field crops vs veg gardens)? Do you have a recipe for a 15L back pack sprayer? Are there recommendations about the frequency of spraying in the tropics? I’m around 12 deg north, sudan/sahel eco region.
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Hi Jared,
Some years back we made neem insecticide, used it and taught others how to make it… but it was a while ago and I’ve forgot a lot of the details. I think we were 13 degrees north, also in the Sahel.
I think from all I read and what I remember is that it works but that its not quite as effective as some of the other commercial insecticides out there. It helps but its a lot more work to make it than buying a ready made insecticide in a bottle and its more work to use as one needs to apply it more often than a lot of other insecticides.
Another thing I recall is that its not rain fast - so basically - if it rains you should re-spray. Now if you have a 4 month rainy season… and you have about 40 rain events then you need to apply it approximately every 3 days… (which is what some of the recommendations I’ve read say).
While many farmers may not put a value on their time… it takes some time to gather the neem leaves and shade dry them and have them pounded and then prepare the sprays. If one collects the seeds - well, it can be costly to pay to have them collected - neems are often common in towns and cities, but sometimes less so in village areas and then its work to pound the seeds and make the sprays. Also, in some places neem oil is incredibly expensive - so the spray shouldn’t be seen as “free”.
I really don’t think you need to worry about it affecting the flavour of the crops - we never observed that.
One other way we used it which wasn’t so much effort was to mix pounded neem leaf, ash and chili powder and apply it down the swirls of corn and sorghum plants to protect them from stem borer and other insects that would munch on the leaves as they came out - the chili was expensive and I would just recommend using pounded neem leaf powder or wood ash - its not expensive and I think it helped. One should apply it just as the sorghum starts booting stage so they don’t get too high on you. I think we applied like a 3 finger pinch full and with the ash maybe a metal bottle cap from a glass coke bottle. Anyhow, if you’re gonna try it, like anything, do it on one row before you think you’re whole crop needs it and wait a week and if it hasn’t done any harm go and do it on the whole crop.
Good luck with it.
Presently working on fermented urine as insecticide. But not yet concluded on the results though colleagues from Rwanda have confirmed of it effectiveness. However collection should avoid drug users and patients on long treatment like HIV ETC.
Hi Dave,
Very helpful response. I suppose the frequency is one reason I haven’t seen too many recent publication on it. Do you know of a village producible way to make a spray rain fast?
The spray could still be useful early/late rainy season when the applications wouldn’t be so frequent. I especially think of late season when the grasshopper population is high.
The ECHOcommunity collection on Neem may have some usable information for this conversation,
particularly the SAWBO video on Natural Insecticide from Neem Seeds
If anyone has good resources to add to the collection, we’ll be happy to include them.
I really liked Dave Rene’s response. A wise person. By the time you concoct your neem spray you will have consumed a lot of time relative to taking the same time and planted some more high value crops to be taken to the market. When you are at the market there will be an agrovet store nearby and if you are squeamish about using a pesticide (cost or health issue either one) consider a Permithrin, often sold as cypermethrin. You wear the appropriate personal protective gear. It will do the job. It is in the same family as a pyrethrin which is taken from the Chrysanthemum (white daisy) which is organic but it is formulated to be a little stronger and have more residual effect and you have to be a little more careful. However, permithrin is the active ingredient for the cream you apply on your skin for scabes and spray on mosquito nets and is sold in nearly every department store. So you could grown your own Chrysanthemum, an effective insecticide, unlike Neem which in my experience is not worth the time for the minimal impact on target pests (most extractions only slow them down). But someone has already made a better formulation and is selling it to you everywhere–Permethrin. The most health conscious people will buy a synthetically (no organic forms) formulated IGR (Insect Growth Regulator). But we generally do not need to be that risk averse. I like to consider a wider range of options. Organic does not mean safer but it is all about an ideology. IGRs, synthetically made, are the safest and then you when you want to choose something else for safety then you have to evaluate the personal protective equipment available and how many times you are going to have to apply it and if the active ingredient has a residue that breaks down by the time you ingest your crop. The problem with organic pesticides is that they have natural active ingredients that can be cancer causing or just as much or more toxic than non-organic and we usually know less about their carcinogenic properties and acute toxicity. Everything should be evaluated on a case by case basis regardless of whether it is organic or not organic. Tobacco, and rotenone, and arsenic are not approved for organic production but they are “natural and organic” but yet some of the plants such as Tephrosia that are commonly used for insecticides are toxic to humans and have rotenone in them. The idea of organic is only useful as it applies to organic matter in your soil which organic and non-organic practitioners both get hyped up about (love) OM. The rest is purely non-scientific ideology. Tithonia is a plant with some pesticide properties as well that is safer. Be careful to not just take anyone’s recommendation as it can waste your time or could be toxic regardless if it is organic. I have read that garlic and chili/hot pepper are not very effective (almost no efficacy) and when I use human urine as fertilizer I don’t put it on the plants and I have not seen much evidence that it is an effective insecticide. Stale urine can have a lot of microbes in it, particularly if stored at lower temperatures.
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Wanted to add that wood ash should be fresh, not rained on and it works to put it in the funnel of the corn/maize plant. However, that is very time consuming and a prepared spray will control it much more rapidly but generally you double the water content of your spray that is recommended and walk at half the speed to get the most effective control of army worm. That way you get more water and the same insecticide level into the funnel which is more effective.
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