Growing Cassava In Thailand

[Lickey]

So all you cassava farmers, its not ants that carry the bug, so what else can it be??

And the rain seems to stop the infestation, now, i wonder, why is that? is it because rain on your chemically killed soil produces new weed shoots [until you spray herbicide again] and thats where the bugs will go? it seems in my mind that the bugs need fresh green shoots, and if your land is killed by cides, the cassava leaves are the only place to find them,

We dont grow cassava anymore, and i have banned cides on the 40rai farm, the fruit trees and banana plants are fed on organic stuff, and are doing well, no sign of bugs like before that decimated 9 rai of pappaya,

No, i am not preaching that you should give up cides ect, but perhaps you farmers with a lot of cassava rai could put aside perhaps 1/2 with no cides, see how it goes?

[Khonwan]

Hi Lickey

How do you then explain the mealybug destruction of cassava crops grown by millions of African subsistence farmers some 30+ years ago when herbicides and chemical fertilisers were never used? No, I do not believe there is any connection between mealybugs and herbicide. Besides, mealybugs are sap-sucking creatures – not much sap in weeds.

Rgds

Khonwan

[somo]

In Kap Choeng south of Surin it is 5 baht per kilo at the moment.

That is very encouraging. Apparently in the Khorat area it is 4.50 so looks like 5.00 for next year is a real possibility. Sure many people will jump on the bandwagon but from what i have heard the price rises are not only due to the bad harvests recently but also increased demand from China and the EU. As Thailand supplies about 70% of world exports the efect has been dramatic and I feel will not be a temporary thing. Africa consumes most of its cassava as does South America but they may well start exporting more but that transition will takes time.

Hopefully the mealy bugs will disappear soon and harvests will improve but because of the above I feel the price will remain strong.

Lickey. It's a shame you gave up on cassava as it is now very profitable.

[Mikki]

hi if you look at the exportprice of starch it was 245 usd/ton in 2007 and now its up to 620 usd/ton. and it looks like the demand will go up Mikki

[Robroy]

I'd be most interested in who has seen/heard of the A lopezi wasp being released in your area.

(A. lopezi is the wasp that kills cassava mealybug.)

The DoA said they would release the wasp across Thailand's cassava areas by the end of the year.

Has the wasp been released near you yet? Kindly report if so.

(If you don't know, the local DoA will.)

I'm curious because I'm on the Cambodian side of the border, and the wasp will benefit us too - when they are released near the border.

Thanks a lot,

Rob

[Robroy]

So all you cassava farmers, its not ants that carry the bug, so what else can it be??

And the rain seems to stop the infestation, now, i wonder, why is that? is it because rain on your chemically killed soil produces new weed shoots [until you spray herbicide again] and thats where the bugs will go? it seems in my mind that the bugs need fresh green shoots, and if your land is killed by cides, the cassava leaves are the only place to find them,

We dont grow cassava anymore, and i have banned cides on the 40rai farm, the fruit trees and banana plants are fed on organic stuff, and are doing well, no sign of bugs like before that decimated 9 rai of pappaya,

No, i am not preaching that you should give up cides ect, but perhaps you farmers with a lot of cassava rai could put aside perhaps 1/2 with no cides, see how it goes?

Ants tend to "herd" the mealybug sometimes, but they're not major carriers.

Mealybug moves (very slowly) under its own steam - from plant to plant, crop to crop.

Rain reduces the infestation simply by washing large mealybugs away. Only those that shelter down low & are small tend to survive the rainy season - but not that many.

However these survivors should begin breeding up around October, when the rains start to diminish. If the A. lopezi wasp hasn't been released in your area by then, one would expect a worse mealybug infestation than last year. In Africa mealybug destroyed about 80% of the crop across 30 countries, before A. lopezi was introduced to bring it under control.

The cassava mealybug lives chiefly on cassava, not much on weeds.

Pesticides will kill the A. lopezi wasp stone dead, which will allow the mealybug to increase. Pesticides are not a good idea anywhere near the wasp.

Hope that answers the questions.

[Khonwan]

I’m sorry, Rabroy, but that muddies the waters since pesticides include herbicides. I think you probably meant insecticides. I know of no research that shows herbicides as harmful to the A. lopezi wasp. Insecticides are obviously harmful to A. lopezi wasps, being insects.

Or do you have any research to the contrary?

Rgds

Khonwan

[Robroy]

No.

Sorry, I've had a crash course in all this, which means I'm not familiar enough with the exact meanings of these terms. Basically, I'd forgotten that a plant can also be a pest.

Meaning that you're right: I should have said 'insecticide'.

Any information as to A. lopezi release in your area? (Anyone?)

I'm very interested in how far the DoA have disseminated it at this stage.

[Khonwan]

We phone our A. lopezi wasp agent (located at the government Sahagon, Mae Poen) from time to time to try to get our hands on some but no joy yet. Although we in Nakhon Sawan are affected by mealybugs, we have suffered much less than Isaan so I suspect we must wait longer until the wasps are released throughout Isaan first.

Rgds

Khonwan

[somo]

Does anyone know how fast the wasps spread once they have been released?

Might give us a better idea on how long it will take to cover the whole country.

[Robroy]

Does anyone know how fast the wasps spread once they have been released?

Might give us a better idea on how long it will take to cover the whole country.

Sources in Korat tell me they have spread at least 30 km since their release about 8 months ago - but that's only a minimum (i.e. as far as my source looked): they may be miles beyond that.

According to which academic paper you read, the mealybug spreads at 100, 150, 300 or 'several hundred' km per year.

As for the wasp, I have read this data & now I cannot find it. In Africa it was something like a minimum of 20 km a month, to the best of my recollection. I'm pretty sure it's not less.

However when they reach you will depend on both this this factor and when/where the DoA release the batch nearest to you. They may have only (say) 30 km to travel to reach your field.

When that happens, BTW, I don't think anyone would mind if you went and caught a few & brought them to your field.

[Robroy]

We phone our A. lopezi wasp agent (located at the government Sahagon, Mae Poen) from time to time to try to get our hands on some but no joy yet. Although we in Nakhon Sawan are affected by mealybugs, we have suffered much less than Isaan so I suspect we must wait longer until the wasps are released throughout Isaan first.

Rgds

Khonwan

Thanks Khonwan.

Would appreciate hearing when they are released.

If you are in the east of Nakhon Sawon they may simply reach you from Nakhon Ratchassima in the next few months. They were released in the mid-west of that province at the start of the year, & have wiped out the mealybug for miles around. They would be well on the way to you now.

Best,

Rob

[Robroy]

This is the guy to keep an eye out for.

But he's smaller than the head of a match - not much bigger than a pinhead, though elongated. not round.

Edited August 15, 2010 by Robroy

[catwho]

I checked the cassava up the road from me that had the wasp put on them about 3 weeks ago, i looked at the leaves which were still clusted from were the mealy bug was,when i broke it open small insects run out of it,they looked dark the same as the wasp i saw put on them weeks ago,the plant itself [stem and leaves] had grown 30/40% more, which between the rain and the wasp,the cassava had done well,where before it was stunted.

A very good point about the insecticides,someone will have to do a lot of weeding around here[by hand].

cat.

[Mikki]

hi yes the A.lopezi can spread up to 20km in one generation and i read that 170km in 10 generations are confirmed (Biological controll in IPM systems in Africa)

Mikki

[Robroy]

I checked the cassava up the road from me that had the wasp put on them about 3 weeks ago, i looked at the leaves which were still clusted from were the mealy bug was,when i broke it open small insects run out of it,they looked dark the same as the wasp i saw put on them weeks ago,the plant itself [stem and leaves] had grown 30/40% more, which between the rain and the wasp,the cassava had done well,where before it was stunted.

A very good point about the insecticides,someone will have to do a lot of weeding around here[by hand].

cat.

Thanks for that update. I see you are in Sikhi, Korat. If this is the same as SIKHIU (on my map), you are very close to the release site, which is at the Thai Tapioca Development Institute (TTDI) at Huay Bong. (The TTDI has led the breeding program.) You are very fortunately placed.

Yes, the wasp has a big effect. Typically you see fresh green tips and lots of growth, and long spaces between internodes.

If you look lower down the main stem you'll see the gnarling and deformation from the old mealybug infestation - & very short spaces between internodes (stunting typical of the mealybug).

Did the insect you see fly as well as walk/run? The wasp does both - but mostly flies.

[catwho]

I checked the cassava up the road from me that had the wasp put on them about 3 weeks ago, i looked at the leaves which were still clusted from were the mealy bug was,when i broke it open small insects run out of it,they looked dark the same as the wasp i saw put on them weeks ago,the plant itself [stem and leaves] had grown 30/40% more, which between the rain and the wasp,the cassava had done well,where before it was stunted.

A very good point about the insecticides,someone will have to do a lot of weeding around here[by hand].

cat.

Thanks for that update. I see you are in Sikhi, Korat. If this is the same as SIKHIU (on my map), you are very close to the release site, which is at the Thai Tapioca Development Institute (TTDI) at Huay Bong. (The TTDI has led the breeding program.) You are very fortunately placed.

Yes, the wasp has a big effect. Typically you see fresh green tips and lots of growth, and long spaces between internodes.

If you look lower down the main stem you'll see the gnarling and deformation from the old mealybug infestation - & very short spaces between internodes (stunting typical of the mealybug).

Did the insect you see fly as well as walk/run? The wasp does both - but mostly flies.

Yeh its sikhui and as mentioned before the ute i saw had TTDI on the side of it, taking GPS and notes on everything.

when i broke the plant opened they just ran,asbove iswhat has happened and spread to other fields.

just on the dide the price of cassava has droped to 3.90bt from 4.90 whitin 2 weeks, anyone have an answer for this.

cat

[gotlost]

On this subject take a look at this.

http://www.thaivisa.com/forum/topic/391573-govt-plans-to-establish-thailand-as-biofuel-hub/

[somo]

Prices in my area of Chayapoum have dropped to just over 2 Baht/kilo!

Bit of a shock as only 6 weeks ago it was about 4 Baht.

Anyone have a theory as to why the drastic drop?

Would also be nice if people post prices in their area so we can get a better overall picture. It has been wet just about everyday with us and one theory is that is that the mills are not so interested in buying at the moment as it is tricky drying the chips.

[gotlost]

Prices in my area of Chayapoum have dropped to just over 2 Baht/kilo!

Bit of a shock as only 6 weeks ago it was about 4 Baht.

Anyone have a theory as to why the drastic drop?

Would also be nice if people post prices in their area so we can get a better overall picture. It has been wet just about everyday with us and one theory is that is that the mills are not so interested in buying at the moment as it is tricky drying the chips.

You have a point about the wet season. Kick in supply and demand everybody and their brother has jumped on this band wagon so I expect an over abundance of product this year which will drive the price down.

[Khonwan]

.... It has been wet just about everyday with us and one theory is that is that the mills are not so interested in buying at the moment as it is tricky drying the chips.

It’s not a theory – it’s a fact. Price always goes down during the rainy season – a fact I seem to have to post every year.

Rgds

Khonwan

[gotlost]

.... It has been wet just about everyday with us and one theory is that is that the mills are not so interested in buying at the moment as it is tricky drying the chips.

It's not a theory – it's a fact. Price always goes down during the rainy season – a fact I seem to have to post every year.

Rgds

Khonwan

I agree. You won't see a price increase until approximately December.

[somo]

I have been told that once stems have been cut they should be left to dry out a little for say 3 or 4 days before planting. Elsewhere I have read planting asap after cutting is best.

I am going up to the country this coming weekend and wanted to cut and imediately plant just a few stems prepared slightly differently as an experiment. Does anyone know if I can do this or should i get someone to cut them a few days before I get there.

Thanks for any advice.

[Khonwan]

Hi Somo

Local Thais tell us the same but we demonstrate time and time again that cutting and planting immediately is at least just as good.

Rgds

Khonwan

[somo]

Hi Khonwan.

Thanks for that.

It seems there are so many myths about farming here.

I have also been told that spraying a pre emergence weed chemical imediately after planting will stop both the weeds and cassave from growing. My instinct tells me this is rubbish and is actual the best time to use pre emergence spraying.

Would appreciate your views on this as well.

Steve

[Mikki]

hi Somo .the price on cassava are 4 bath kilo as today in my area( Bueng Sam Phan), wich would be located between you and Khonwan . regards Mikki

[Khonwan]

Sorry, Steve, just noticed your post.

We have been spraying pre-emergence weed killer immediately after planting for some 2-3 years now. We use Sumisoya (flumioxazin) – 550 baht for 100g, enough for 5 rai. We spray day after planting – you can spray same day, immediately after planting your cassava, or within 3 days. It works really great, as long as it doesn’t rain for a day or so. The chemical doesn’t affect the cassava setts before they start to bud, hence the need to spray within first 3 days. We would not consider going back to our previous non-use of pre-emergence herbicide.

Rgds

Khonwan

PS. Mikki: I can’t yet quote a price for my area since the factories are not yet buying in Nakhon Sawan / Kampaengphet; I’ll be very pleased with 4,000 baht per tonne though!

[somo]

Thanks for the info guys.

I will definiteley use a pre emergence chemi next planting. Weed killing was a major expense for me last year so trying to stop them even appearing.

4 Baht/kilo is great. will post a price from Chayapoum after the weekend.

[somo]

Price in my area is currently 2.65/kilo. This time last year it was 1.45

[maipasathai]

A few years ago I found a graph showing the average monthly cassava price for the last 5-6 years. Tought it was on the "thaitapiocastarch" but nothing there. Anybody have a clue?

Have 50 rai at 18 months in October but as I read this forum maybe better to hold a few months more.