Insect pests, plant diseases and integrated pest management

[drtreelove]

16 minutes ago, scubastephen said:

This produce I've used in Australia. Sprayed walls and veranda floors to stop invasion of Portuguese millipedes. Found it killed flys and controled spider infestations for up to 3 months under roofed areas. Which is the reason why I'm looking for it in Thailand.

Sent from my SM-G935F using Thailand Forum - Thaivisa mobile app
 

For that purpose I would recommend Chaindrite Stedfast 30 SC, a bifenthrin product which has an even better knock down and longer residual effectiveness than permethrin an its widely available at most garden centers, building supply and supermarkets, and Lazada: 

 

https://www.lazada.co.th/products/chaindrite-stedfast-30sc-30-250-i106082420-s106763063.html

[Tommyknocker]

Hello everyone! I recently retired outside Bangkok and enjoy reading these forums. I now find myself needing some advice from you seasoned experts. 

I recently put in 50 “sai gowlee” plants along two walls for privacy. I dug down a foot, replacing the clay with good dirt before planting. Recently I have noticed leaves going brown, as well as many yellowing and falling off. I don’t know if I have a pest problem or some type of fungal infection. I can’t find the English equivalent name for this plant to help diagnose the problem. Any help from you all would be greatly appreciated! I am enclosing photos. Thanks, and sorry for the long winded post!

[cooked]

7 hours ago, Tommyknocker said:

Hello everyone! I recently retired outside Bangkok and enjoy reading these forums. I now find myself needing some advice from you seasoned experts. 

I recently put in 50 “sai gowlee” plants along two walls for privacy. I dug down a foot, replacing the clay with good dirt before planting. Recently I have noticed leaves going brown, as well as many yellowing and falling off. I don’t know if I have a pest problem or some type of fungal infection. I can’t find the English equivalent name for this plant to help diagnose the problem. Any help from you all would be greatly appreciated! I am enclosing photos. Thanks, and sorry for the long winded post!

 

 

Leaf miner? Possibly the plants are weakened by transplanting (planting too deep is a common problem), too much water or too much sun? This leaves them open to insect and possibly fungal attack once the insects have left their excrement all over the place. 

Anyway, if the plants are planted at the same depth as they were in their containers, maybe change watering and buy a combi spray insecticide / fungicide.

Difficult to say without actually standing in your garden. You did well to change the soil, maybe you bought the spent mushroom manure you see everywhere and it has sunk down, taking the plants with them?

[Tommyknocker]

1 hour ago, cooked said:

Leaf miner? Possibly the plants are weakened by transplanting (planting too deep is a common problem), too much water or too much sun? This leaves them open to insect and possibly fungal attack once the insects have left their excrement all over the place. 

Anyway, if the plants are planted at the same depth as they were in their containers, maybe change watering and buy a combi spray insecticide / fungicide.

Difficult to say without actually standing in your garden. You did well to change the soil, maybe you bought the spent mushroom manure you see everywhere and it has sunk down, taking the plants with them?

Thanks for your quick reply! The dirt I bought was tamped down

and the plants were put in at the same depth as they were in the

pots. I then filled in between them, even though the root balls were touching, to keep them closely spaced. They don’t get a lot of sun, but there still seems to be quite a bit of new growth over the

entire plants (outward and upward). I’ve been watering twice weekly since we get no rain. I’ll see if I can find the combo spray and give it a shot. The tops of the plants seem to suffer the most, so possibly the new growth and tender leaves are being attacked.

I appreciate your help. Lots to learn about gardening here in Thailand, compared to what I experienced back home!

[Time to grow]

I posted this in another section but this one seems more relevant. I am looking for a source of three organic garden amendments, two of which to deal with grubs in my raised beds and one as an additive to an aquaponics system. Specifically, some beneficial nematodes (Heterorhabditis Bacteriophora), some Milky Spore, and some soluble kelp powder. I have several raised garden beds with exceptionally rich soil that the grubs just love. I understand the Nematodes and Milky Spore are particularly good at eliminating grubs. These products are readily available in N. America and even other countries of SE Asia but I can't find a supplier in Thailand. Due to the nature of the products being live, it seems importation is complicated.

 

I am not sure how Thai farmers control grubs other than with harmful pesticides but I am open to other methods if anyone knows of a control.

[drtreelove]

On 6/8/2019 at 7:24 AM, Time to grow said:

I posted this in another section but this one seems more relevant. I am looking for a source of three organic garden amendments, two of which to deal with grubs in my raised beds and one as an additive to an aquaponics system. Specifically, some beneficial nematodes (Heterorhabditis Bacteriophora), some Milky Spore, and some soluble kelp powder. I have several raised garden beds with exceptionally rich soil that the grubs just love. I understand the Nematodes and Milky Spore are particularly good at eliminating grubs. These products are readily available in N. America and even other countries of SE Asia but I can't find a supplier in Thailand. Due to the nature of the products being live, it seems importation is complicated.

 

I am not sure how Thai farmers control grubs other than with harmful pesticides but I am open to other methods if anyone knows of a control.

Try this:

http://www.entomology.wisc.edu/mbcn/kyf607.html

 

I haven't seen a predatory nematodes source, but others may have that information.

 

Kelp solutions are available, mostly in small containers, a liter or less, I haven't seen bulk kelp meal. It's a wonderful soil amendment and trace mineral source, but won't be a direct control for grubs. 

[bannork]

The last few days my young namwa banana trees have been attacked by  caterpillars, hatched from eggs left by butterflies in the yet to unfurl banana leaf, known as bai muan in Thai.

I know there are chemicals I can use but I'd rather use something organic. 

I've taken to inspecting the trees (250) twice a day and have been eliminating caterpillars found, but I fear the butterflies will return again and again.

Any helpful suggestions would be much appreciated.

[xylophone]

1 hour ago, bannork said:

The last few days my young namwa banana trees have been attacked by  caterpillars, hatched from eggs left by butterflies in the yet to unfurl banana leaf, known as bai muan in Thai.

I know there are chemicals I can use but I'd rather use something organic. 

I've taken to inspecting the trees (250) twice a day and have been eliminating caterpillars found, but I fear the butterflies will return again and again.

Any helpful suggestions would be much appreciated.

I read an article in a New Zealand magazine, by someone who wanted to kill some caterpillars and little beasties, but wanted to do it organically, so a spray made from washing-up liquid and water was proposed, and apparently it worked very well!

[drtreelove]

2 hours ago, bannork said:

The last few days my young namwa banana trees have been attacked by  caterpillars, hatched from eggs left by butterflies in the yet to unfurl banana leaf, known as bai muan in Thai.

I know there are chemicals I can use but I'd rather use something organic. 

I've taken to inspecting the trees (250) twice a day and have been eliminating caterpillars found, but I fear the butterflies will return again and again.

Any helpful suggestions would be much appreciated.

 

Insecticidal soap is good as a contact spray, but is not systemic and cannot get inside the curled leaves and it does not have long term residual effectiveness for repelling the adult moths or butterflies from laying eggs.  Neem seed extract (Azadirachtin concentrate) is better as a repellant and reproductive disruptor. but any organic insecticide needs frequent repeated applications. And as your banana plants grow this makes application more challenging and expensive. 

But lets get to the heart of the problem.  In my opinion your plants are not being managed properly so they are susceptible to pest and disease and water deficit issues.

From the photos they appear stunted and pale, indicating extreme nutrient deficiencies. Nutrition matters for pest management.

They are wilty, indicating water deficit. There is no mulch except a few strands of straw, and that is not mulch. 

I have grown namwa bananas in two locaions in Chiang Mai and also in Samut Prakan and never had pest or disease problems. But I  improve the soil with mineral and biological amendments and fertilize with manure. I mulch the soil surface and water regularly. 

BTW, that's a lot of damage; you may have snails or slugs feeding at night too. 

[bannork]

36 minutes ago, drtreelove said:

Insecticidal soap is good as a contact spray, but is not systemic and cannot get inside the curled leaves and it does not have long term residual effectiveness for repelling the adult moths or butterflies from laying eggs.  Neem seed extract (Azadirachtin concentrate) is better as a repellant and reproductive disruptor. but any organic insecticide needs frequent repeated applications. And as your banana plants grow this makes application more challenging and expensive. 

But lets get to the heart of the problem.  In my opinion your plants are not being managed properly so they are susceptible to pest and disease and water deficit issues.

From the photos they appear stunted and pale, indicating extreme nutrient deficiencies. Nutrition matters for pest management.

They are wilty, indicating water deficit. There is no mulch except a few strands of straw, and that is not mulch. 

I have grown namwa bananas in two locaions in Chiang Mai and also in Samut Prakan and never had pest or disease problems. But I  improve the soil with mineral and biological amendments and fertilize with manure. I mulch the soil surface and water regularly. 

BTW, that's a lot of damage; you may have snails or slugs feeding at night too. 

Actually they are fine for both water and organic fertilizer.

Looks like BT is the route to take.

 

[paddypower]

On 9/23/2018 at 11:45 AM, drtreelove said:

For that purpose I would recommend Chaindrite Stedfast 30 SC, a bifenthrin product which has an even better knock down and longer residual effectiveness than permethrin an its widely available at most garden centers, building supply and supermarkets, and Lazada: 

 

https://www.lazada.co.th/products/chaindrite-stedfast-30sc-30-250-i106082420-s106763063.html

this forum doess not seem to be active. I have these yeppow flying pests that attack/eat my orchids. I tried spraying teh orchids with a soap/water mix - no joy.  any advice?

[drtreelove]

23 hours ago, bannork said:

Actually they are fine for both water and organic fertilizer.

Looks like BT is the route to take.

 

Those plants look better than the sickly one you showed first. The healthier plants will resist infestation, especially if your organic fertilizer is mineral balanced and has the 5 basic micronutrients as well as trace minerals. Avoid high NPK, high salt index fertilizers that are a pest magnet. 

 

Thats a big planting, a lot of investment.  Mono-cropping is risky, consider some intercropping with plants that attract beneficials, pest predators and birds for natural control. walk it every day to monitor for pest activity and be able to implement early intervention. 

 

Overhead watering can be problematic and invite foliar fungal disease, and weeds, and water loss from evaporation.

 

B.t. has to be ingested by the caterpillar through feeding, so timing, placement and a spreader-sticker are important. And the timing has to be perfect to be effective. Monitor for caterpillar stage of development. 1st and 2nd instar stage is best for B.t. apps. Later instars, 4th and 5th may not be controlled by B.t.

 

Applicator should use a respirator with B.T., not just a mask. Microbial proteins can cause respiratory disorders, I learned the hard way. I have sprayed a lot of B.t. thinking its "organic" so no PPEs needed. wrong. 

 

If mine, if mechanical control isn't practical, I would first determine if the moths were still flying in and laying eggs, or was it an early spring infestation that has come and gone. Some moths/butterflies have a very limited, once annual life cycle. Some have multiple life cycles a year.  If determined to be a real and present problem, target the adult moth emergence, egg laying stage, with botanical repellent, so you don't get caterpillars to begin with.  Azadirachtin, wood vinegar, aromatic oils, rosemary, clove etc. 

 

 

[drtreelove]

Another issue to be aware of with a banana plantation is soil borne pathogens. The big one worldwide is the devastating Panama disease, a fusarium wilt. It only goes to Cavendish variety as far as I know, but there are other pathogens, and they may not be detectable until disease is advanced and difficult or impossible to control. 

 

Prevention is the best medicine. Soil testing, high-nutrient-density mineralized soil building, inoculation and enhancement of beneficial soil biology, biological fungicides and cover cropping are the way to go for an organic program approach in my opinion. 

[bannork]

There are not only bananas on this land. There are 6 rows of 68 bananas per row on the left of the irrigation pipe, underneath the pvc I have planted hardwood trees every 5 metres, they can replace some of the bamboo supports in a couple of years, and to the right of the pvc I have started growing vegetables and herbs on the stretches that have suitable soil, 

Pak boong in the ditches between the rows, as well as some fish perhaps, bla tapien, ปลาตะเพียน is the obvious choice.

The moths infested 90% of the banana trees, both strong and weaker. A Thai told me it was a rainy season problem, but like you say it may be just an annual event so so far I've refrained from applying BT.

[drtreelove]

On 7/1/2020 at 6:28 AM, drtreelove said:

Another issue to be aware of with a banana plantation is soil borne pathogens. The big one worldwide is the devastating Panama disease, a fusarium wilt. It only goes to Cavendish variety as far as I know, but there are other pathogens, and they may not be detectable until disease is advanced and difficult or impossible to control. 

 

Prevention is the best medicine. Soil testing, high-nutrient-density mineralized soil building, inoculation and enhancement of beneficial soil biology, biological fungicides and cover cropping are the way to go for an organic program approach in my opinion. 

I just happened across this article on IPM for caterpillar control.

 

https://plantcaretoday.com/caterpillar-control.html#:~:text=Coat your plants thoroughly so,the organic Spinosad insect spray.

 

Note the time frame: "If you have a lot of moth caterpillar eating leaves in your garden, you can count on them doing a great deal of damage to your vegetable production and consuming quite a bit of your crop during the two or three weeks between their hatching and wrapping up in a cocoon." 

 

Most people don't notice caterpillars until the later larva stage when feeding is almost finished before the pupa stage. So spraying is a panic reaction and may not achieve much reduction in plant damage, it's almost done. Consider this, remember what happened this year, put it on your calendar, and next year be prepared to start monitoring for baby caterpillars a month or two before you noticed them this year. 

 

"Coat your plants thoroughly so the caterpillars ingest the product when they eat. This organic solution should be used frequently (every 3 to 5 days) until your caterpillar population is under control." 

 

That's more frequent than I've ever had to use Bt, but a follow up spray or two is usually necessary. For an effective control standpoint, as well as economics, (the time and materials costs can add up,) so you want to get the timing right. 

 

 

 

 

 

[bodga]

On 2/10/2009 at 9:09 PM, drtreelove said:

Neem oil?

Banned  in the UK

[Tawng]

Anybody know what is doing this to my young mango leaves? It seems to happen at night but I haven't managed to spot the culprit. The cut leaves are not even eaten, just left lying around on the ground. Vandalism!

[drtreelove]

I haven't seen this in mango, but I would suspect a cutworm or leaf cutter bee. If it's happening at night, a cutworm is the most likely suspect. 

 

https://en.wikipedia.org/wiki/Cutworm

 

https://www.gardeningknowhow.com/plant-problems/pests/insects/leaf-cutter-bees.htm

 

Go out at night and look for pest activity, inspect the stems and under side of leaves closely with a flashlight, to try and get a positive identification. 

 

Since your tree appears to be in seedling stage and not a fruit producer yet, you could use a chemical insecticide barrier application, like the pyrethroid "bifenthrin", active ingredient in Chaindrite Stedfast 30SC. 

 

An organic approach would be to spray the foliage and drench the soil with a neem seed extract product, Azadirachtin concentrate, a repellent and reproductive disruptor . And/or a soil treatment (where cutworm larvae may reside during day) of Metarhizium, or Beauveria, entomopathogenic fungi that attack the pest insect's cuticle. 

 

But there is also the wait and see approach, because the tree will not likely be killed, the insect pest will pass the feeding stage of it's life cycle and the tree will re-foliate and outgrow the susceptible stage of growth. Avoid high NPK chemical fertilizers that stimulate excessive vegetative growth which is tender and attractive to pests. Enrich the soil with compost, and complete organic fertilizer. 

 

Don

[Tawng]

Thanks for that. Cutworms of some kind sound quite possible and could explain why they just let the leaves drop to the ground (to eat later). They’ve taken all the young leaves off this sapling but they have appeared on other young mango trees. Next time it happens I’ll have a more careful look at night and maybe try a physical barrier around the stem like a ring of outward-facing sticky tape as a first line of defence.