Growing Cassava In Thailand

[Lickey]

Inspect your cassava stems for ants, you will see them running up and down the stems with small white blobs on their backs, Ants transport the bugs from stem to stem and feed off the sugary shit they produce,

We lost 9 rai of Papaya to mealy bugs, we tried all the herbal remidies suggested, we planted cassava only to get infected again, [the ants keep the bugs in there nests to use when they want] I found a chemical [hate the stuff,but needs most] that killed of the ants and probaly a lot of benifical insects, but it stopped the rot!!, belive it or not, they attacked the rubber trees, munching away at the new top leaves, again, ants were seen up and down the trunks,

Personally, i dont think the rain washes them away, i think the ants cant be bothered with a 2 mtr climb when all the lush vegatation is coming through on the ground,

Control the ants and you will control the mealy bugs,

try this site,the first farmers cut copy and paste,

http://nationalzoo.si.edu/Publications/Zoo.../antfarmers.cfm

Edited May 9, 2010 by Lickey

[Robroy]

A bit of an update:

Testing in Thailand of the A. lopezi parasitoid wasp (the one that destroys cassava mealybug) is now complete: it's safe! I.e. it doesn't eat anything else.

The A. lopezi were released at Rayong and TTDI, Huay Bong.

These were small scale releases, and now that the wasp has passed the safety tests it will probably be approved for widescale release.

Even from the small scale releases it should spread eventually to a mealybug infestation near you. But the widescale releases will expedite that greatly - when they come, which I'm guessing will be by the start of the next dry season. (The ideal time for widescale release.)

The rains, when they come, will wash away most of the mealybugs - until the next dry season that is, when they will breed up again.

That brings us to this:

I'm not sure if anyone realises it, but SE Asia is in the grip of an El Nino climate event since mid-2009.

This probably accounts for the low rainfall, and the extreme heat we are experiencing right now.

El Nino events typically last 12 months, and this one is due to start decaying any time now:

http://iri.columbia.edu/climate/ENSO/curre.../QuickLook.html

If that happens (they occasionally go for up to 18 months) we should be on track for a 'normal' June, or at least a 'normal' July.

[Lickey]

Im looking for a bit of information here, so thanks for any help you can give me

How does this pink/yellow/white lifeless globule [with no wings or legs ] get to the top of a cassava stalk?

Shaking the stalk has little or no effect on them?

Using a motorized pressure spay from underneath might dislodge 80% but rain on top of the leaves clears them all?

Thanks, Lickey,,

[IsaanAussie]

Im looking for a bit of information here, so thanks for any help you can give me

How does this pink/yellow/white lifeless globule [with no wings or legs ] get to the top of a cassava stalk?

Shaking the stalk has little or no effect on them?

Using a motorized pressure spay from underneath might dislodge 80% but rain on top of the leaves clears them all?

Thanks, Lickey,,

Lickey mate,

Pray for rain. Who cares how it got there?

Isaanaussie

[Lickey]

IssanAussie, I dont do cassava anymore, once bitten,twice shy, biggest problem was the Wall St crash i suppose, then came the mealy bugs which destroyed 9rai of Papaya in a matter of weeks, the bugs then got onto the cassava, a lot of plants didnt survive, and what did [after spraying the ground] we got 1bht 4st for, my bookwork suggests a loss of 18,000bht, start to finish in 10 months, so im not going through that again.

What im trying to do is tell the good cassava farmers on here that a lot of the responsibilty of mealy bugs spreading are ants, Yes, by all means, bring on the wasp, the ladybird beetle, whatever you want, but the ants will protect the bugs against natural predators,

try this link, www.mealybugs ants paste into Google search.

Edited May 13, 2010 by Lickey

[Khonwan]

Ants can be associated with cassava mealbugs but this is not necessarily the case. I have spoken with Somo: neither of us have found ants attending our mealybugs. I’ve just walked an infected area of 10 rai, plus adjacent fields: zero evidence of ants.

It is reported in Africa that attendance by ants causes a 50% decrease in effectiveness of the Lopezi wasps so measures to rid or prevent ants are sensible.

Dish-detergent (at any strength) no longer works for me in my attempts to control mealybugs. Propriety specialized pesticide was also tried by me but proved expensive and useless. I have Rayong 9 and Huay Bong 60 – I, and everyone else in my area planting this variety, report that Rayong 9 is particularly prone to infestation; Huay Bong 60, whilst not immune, appears to be more resistant. Fortunately, Huay Bong 60 forms the vast majority of my crops.

I recently (this month) sold the majority of my Rayong 9 twelve-month-old trees for 3-4,000 baht per rai…despite the obvious mealybug damage. I was hoping to leave the tubers for a further 6 months but the new growth is now also heavily infected, which will cause the tubers to dry out. I am therefore harvesting these tubers today; I will receive 2,250 baht per tonne (down 50 baht from last week due, I’m told, to end-point delivery problems associated with the Red Shirts). My Huay Bong 60 will be harvested around November, at 18 months (when I suspect the price may reach 3,000 baht per tonne).

I have recently planted around 17 rai (no mealybugs so far) and intend to plant another 75 rai next month. 9 of the 17 rai just planted came from the least damaged of my Rayong 9 trees – the setts were first dipped in a solution containing a pesticide for mealybugs, a pesticide for ants, and zinc (probably the most limiting of the minor nutrients) before being planted.

Although we have only started harvesting Rayong 9, the 12-month tubers are proving smaller than similar aged and spaced Huay Bong 60. I may well replace the 9 rai of newly planted Rayong 9 next month with Huay Bong 60.

Rgds

Khonwan

[somo]

I can confirm that I have no ant problem but a big mealy bug one.

Having said that my plants are mature and none died over the dry season although they looked very sad and growth was inhibited.

We have recently had a decent amount of rain in Chayapoum and that has made a big difference.

The plants are sprouting new leaves and the mealy bug although not gone do not seam to be infesting this new growth.

I too have just sold off 15 rai of stems and intend to leave the plants for another 7 or 8 months but may like Khonwan need to harvest if the mealy bug infest the new growth.

The trouble with that is the newly planted setts may be even more vulnerable than the older ones that have a half decent growth in the ground already. Hopefully now the rains are here the stems will regrow faster than the mealy bug eats them.

I think the only solution to the problem will be the lopezi wasp as it was in Africa but that may take 2-3 years to cover all the infected areas. Until then think the golden rule must be to only plant once the rainy season is in full swing.

On a more distressing note there have been a few suicides in my area as farmers have seen their livelyhoods disappear. On top of that some villagers have been experimenting with stronger and stronger chemicals (for dipping the stems in prior to planting) and have ended up seriously ill in hospital.

[Robroy]

I can't add much as my knowledge is entirely theoretical (I'm not a farmer).

The El Nino 'should' end in about June, & the rains come in earnest as per normal, and that should in time wash away the mealybugs. (Not overnight.)

At the end of the year when the rains stop the mealybugs will breed up again - at least as big & bad as before.

Nothing works against them other than A. lopezi.

A lopezi has been released in a limited way in the areas I mentioned above, and it is hoped that widescale releases will occur at the start of the next dry season.

I've not heard about ants attending mealybug, so can't comment on that.

Even the big Thai companies (e.g. cassava starch producers) are in cashflow & raw materials trouble because of mealybug right now.

It's a national disaster of sorts. However whilst the political parties slug it out, the entomologists at the Dept of Agriculture are quietly doing their work (importing, testing & releasing A. lopezi) - making this response to mealybug the fastest of any country ever to my knowledge.

Basically, when the A. lopezi reach your area your cassava will probably be saved; & anything you can do to expedite that will obviously save it earlier.

[somo]

Thanks Robroy.

Please keep the info flowing as soon as you get it especially as to where we might be able to get our hands on some lopezi wasps.

Steve

[Robroy]

Thanks Robroy.

Please keep the info flowing as soon as you get it especially as to where we might be able to get our hands on some lopezi wasps.

Steve

Steve,

Officially I don't think the wasps are available for the general farmer population - some formalities need to be completed first re the smallscale release/study.

But if I were an affected farmer I would identify the release sites around Rayong (perhaps via Dept Ag), go there with a jar or three (and perhaps an aspirator - a device for collecting bugs), & ask the officials if I could take some A. lopezi away with me.

Then, if permission was given, I'd take them to my farm & release them. (Bit of a risk of course: permission may not be given.)

It depends on the scale of damage you face of course. If minor, probably not worth the time & effort.

How's the rain situation? That should be getting rid of the mealybug anyway. In northern Cambodia (adjacent to the south of Isaan) we have had quite a bit of rain, & the mealybug are starting to disappear.

When this El Nino ends the drought should end too - perhaps next month if the averages hold.

The real challenge will be December-ish - when the rain ends. Then the mealybug will breed up bigger than ever. (My goal for Cambodia is to be ready for that with stocks of A. lopezi, which the Thai Ag Dept has very kindly agreed to supply us with.)

[somo]

The rain in my area (Chayapoum) started a few weeks ago although intermittent and has done wonders for my rather sad looking plants. New leaves growing so the shrivelled up ones are lower down now. They are mostly between 8 months and a year old and I will be leaving them for another rainy season before harvesting. The rains usually stop here end Oct/early Nov so will try to get some wasps around then. Hopefully the agricultural department will be releasing them in multiple areas anyway and not just in Rayong but as you say it would be nice to get some myself.

[Mobaan]

I want to try the 18-20 month growing cycle thing near Udon. Nobody around here has ever done it ,that I know of . Other than ignorance , are there perhaps other reasons?

This coming October I will have access to newly purchased land . It has been in Cassava for God only knows how long . Good sandy soil ,no drainage problems.

So after the last harvest is off the land I want to plow deep ,twice, at different angles and the plnt mung beans . What are those beans called in Thai? People know about them ,but nobody has the time and the patience to do this .

Then next May (when the rains come ???) I am ready to plant.

Does that sound like a plan to follow?

[Khonwan]

Hi Mobaan

Got your PM – it is a pity that more cassava growing members (or lurkers) don’t also chip in from time to time to offer advice.

Having said that, I’ve already addressed part of your query in my OP. You’ll even find the Thai name for mungbeans written by me in English phonetics and Thai script. Nearly all my thai neighbours grow mungbeans – usually before a June/July planting of maize. The mungbean 2-month period suits my cassava cycle also since I normally plant cassava in June. You should note that mungbeans are planted around mid April and harvested around mid June.

18-20 month cultivation is carried out by more than a few of my Thai neighbours. Cash flow problems prevent others following this system.

Other than having to delay your cassava planting until June (rather than May), your plan is good.

Rgds

Khonwan

[Mobaan]

Thanks for all the info in this thread.

Still a question to the mung beans. I have read throu the entire thread ,but have not found a mention on how to plant those beans . Just starting out ,not having own equipment-can I just broadcast seed those beans ,followed be a shallow discing? I could even increase the seeding rate (Which is what anyway) to account for bad emergence.

When we have access to the land by November I think I plant one crop of beans ,they might be ready to be ploughed in as greenmanure by February. Then plant another crop -same,same beans ,or something ,again as greenmanure only in order to have the field ready for the cassava planting in June.

Is it possible to buy/needed to have fungicidal seed treatment for those beans?

[maipasathai]

Hi Mooban,

I also wanted to do some soya or muang been on the cassava fields. Took some soil and got it analysed in Udon and the outcome was that they didn't recommend to do beans in that soil but for cassava it was OK. Suggest you go for a soil analyse (it's for free).

[Mobaan]

That is a bit strange . We will plant the beans only as greenmanure, not going for any yield .

I would not take these "recommendation" too seriously.

Are you in the Udon area ? Maybe we need to pool our local wisdom-you could PM me.

A few weeks ago we heard that Amphur will have Cassava stalks of the nwer varieties available for sale at 3 Baht each. Now , that is out -sorry.

Also we tried to register for the "extra" 20-30 Satang the "government " was supposed to pay to "help" the farmers. Sorry again , only can do on land owned outrigth with a Chanot or Nor Sor Sam ,can not do on land to which you do not have any official papers (we call it "Army land " around Udon.).

Thats the latest.

[Khonwan]

Hi Mobaan

Detailed discussion of mungbeans is off-topic for this thread so I’ll limit my comments here. Please open a new thread should you wish to invite more information on this subject (from others as well as me).

You are not likely to be able to harvest mungbeans cultivated in November but that may not matter to you should you only be interested in green manure. In that case, I would recommend broadcasting at least 5kg per rai followed by shallow discing (harrowing). You shouldn’t have to spray insecticides since you won’t have beans to harvest at that time of the year.

Mungbeans planted around April can be harvested and sold two months later – the remaining leaves and roots continue to provide excellent green manure. These should be ploughed in around 2 (to 3) weeks before planting your cassava or other crops. We (in truth, my wife in the case of mungbeans) plant mungbeans for harvesting. We broadcast 4.0-4.8kg/rai (can be more dense if only for green manure).

Buy your mungbean seeds from other farmers if you are only interested in green manure and don’t intend to harvest beans. Commercial seeds cost me around 50 baht per kg two months ago whilst I just sold harvested beans for just over 38 baht per kg (the farm-gate price should decrease over the next month). At least in my locality, the beans are purchased and sold by the “tang”, a measure of volume – in the case of mungbeans, one tang equals 16kg.

I recommend this site for further excellent info on cultivation of mung beans for harvest: Australian Mungbean Association - Home Page

Rgds

Khonwan

PS. I’ve written this in a bit of a rush but I hope it is not too disjointed.

[Mobaan]

Right on mate -thats what I neede to know .

Thanks

[Robroy]

Would be interested to know how cassava growers are going with the mealybugs. Rain knocking them off, or still causing trouble?

Also I'd be interested in whether you are getting enough rain - i.e. something like the average for June.

Kindly specify province so I can look you up.

[somo]

In Chayapoum May saw some rain which gave some good growth to the plants without mealy bug on top so don't think they are breeding. First two weeks of June were dry but this last week had some decent rain so not too bad overall.

Price of cassava is now just over 3 Baht/kilo there and with the usual excitement people are talking of 4 Baht next year (Quite possible but seeing is believing) which would be geat as I will not be harvesting till then. I have cut and sold nearly all my stems and the new growth has very little mealy bug but is infected with "pia Deng: another variety of pest but that seems to be curable with the right chemicals.

[Robroy]

Just did a trip up to the Thai border on the Cambodian side.

There are 20,000 hectares under cassava in Banteay Meanchey province - which is opposite Aranyaprathet.

The cassava mealybug is in all four Banteay Meanchey districts on the border. The bug is moving south, & we expect it to be in Battambang province by the end of the rainy season. (Battambang is roughly opposite Wang Sombun & Khiong Hat on your side.)

However the large mealybugs have been washed away by the rain, leaving only pretty small ones right now, which do not appear to be doing much harm.

On both sides of the border, our crunch will come in about 3 months (Octoberish), when the rains are likely to ease off.

That will allow he mealybug to breed up again. In Africa in the 1980s mealybug wiped out 80% of the cassava in 30 countries, & my guess is that it will wipe out 80% of Thai & Cambodian cassava this year if not stopped. However that's a hunch - no-one really knows what will happen.

The Thai DOA & TTDI are doing an excellent job in breeding up the only known antidote - the wasp A. lopezi. They will hopefully get permission to release them soon. Permission has already been granted in Cambodia - we are now awaiting the Thai permission so we can get supplies.

How is the mealybug situation there now? Much damage? Or quiescent?

[Robroy]

The Thai release of A. lopezi began over the weekend:

http://www.nytimes.com/2010/07/19/world/asia/19thai.html?_r=2&hp

[somo]

Good news!!!

Thanks for the update

[Mikki]

Hi everyone In the area(bueng sam phan district ) where we have our farm there have been problems with mealybugs and lack of rain during the last months. People have alredy lost their crop mostly due to the fact of planting cassava and dident get any rain.

we lost about 2 rais my guess is that the soil got overheated it has lots of small stones in that part of the field But it rained last week and the rest looks ok I tried to explain to the mrs about the wasp and asked her to speak with her mother to look if there is any information about any realease in Petchabun.............now i have a headache is there anyone that heard of it ? tried to lok on the net but couldent find anything

Im not in thailand at the moment and its my second year so im sorry that i cant tribute to this forum ........... but thanks to all information you guys have posted

Regards Mikki

Edited July 21, 2010 by Mikki

[Robroy]

The wasps have been bred by the Thai Tapioca Development Institute in Huay Bong village about an hour northwest from Korat town. They are in the fields there, and have successfully cleaned up the mealybug.

With the recent formal release (see above link) responsibility for dispersing them has gone to the Department of Agriculture. They aim to cover isaan with them by the end of the year.

To discover when they will be coming to your area, you need to contact the DOA. The wasp is named A. lopezi.

[pete_r]

Toni Bellotti from CIAT on the lopezi wasp:

http://www.blip.tv/file/3640329

[Khonwan]

Toni Bellotti from CIAT on the lopezi wasp:

http://www.blip.tv/file/3640329

Just watched it, thanks. The correct address, though, is http://blip.tv/file/3877218

Rgds

Khonwan

[somo]

Thanks for the link.

Hopefully by the time the rains finish there will be plenty of wasps around to kill of the expected revival in mealy bug infestation.

By the way the price of cassava hit 4.00 Baht/kilo in Chayapoum recently.

Any ideas on the outlook for next year. Up to 5.00 Baht or back to around 3.00 Baht.

My bet is 4.00 + but then I,m an optomist

[catwho]

Thanks for the link.

Hopefully by the time the rains finish there will be plenty of wasps around to kill of the expected revival in mealy bug infestation.

By the way the price of cassava hit 4.00 Baht/kilo in Chayapoum recently.

Any ideas on the outlook for next year. Up to 5.00 Baht or back to around 3.00 Baht.

My bet is 4.00 + but then I,m an optomist

[/quote

I would have to agree, but hopes it dose stay up there,here in shikui its 4.15, with the drought and a lot of farmers around here are trying there luck ,time, and money to try for quick turnover of veggies or chille, and now the planting of corn,where as before most farm here only did sugar cane ,cassava,corn,i'd say the cassava average, for thailand will be down,along with the mealy bug probs.

i think we have at least 2 good seasons of good cassava prices,till the thai farmers do the usual thing and get on the ban wagon and have over supply.

cat

[gotlost]

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