Caterpillars on tree

[bubba45]

I'm hoping someone can give some advice regarding the caterpillars pictured below.  This tree is off in a corner of the yard and we just noticed this infestation yesterday.  My question is, can I just wait these out, or are they doing serious damage to the tree? 

 

Advice appreciated.

 

[samuijimmy]

I would say trees have survived millions of years, rarely will insects kill a tree... let nature take care of itself...

[bubba45]

Appreciate that, jimmy, that's my inclination.  But I wanted to make sure I was not making a mistake.

 

Should I have posted this somewhere else?  I see dozens of comments, sometimes, to simple "what's this snake" question.  I would think someone would have a more specific answer in regards to this caterpillar.

 

Thanks.

 

[samuijimmy]

8 hours ago, bubba45 said:

Appreciate that, jimmy, that's my inclination.  But I wanted to make sure I was not making a mistake.

 

Should I have posted this somewhere else?  I see dozens of comments, sometimes, to simple "what's this snake" question.  I would think someone would have a more specific answer in regards to this caterpillar.

 

Thanks.

 

 

Question OK where it was!  

 

Perhaps the locals will collect them and eat them!

 

I look after this Gardening site too... more for southern areas, but after just going to Udon Thani, a few weeks ago, the plants and bugs are pretty the same... slight difference in timing and seasons .

If anyone asks a question here, just say roughly where you are! 

 

http://www.thaivisa.com/forum/topic/354759-gardening-on-the-islands/?page=38

[drtreelove]

I don't know this specific caterpillar, but in general, an infestation with numbers like that will see the caterpillars defoliate the tree. With adequate water, the tree will probably refoliate. Defoliation may not kill the tree, but can cause extreme physiological stress, that in combination with other factors, like water deficit, can contribute to decline and mortality. 

 

Insect pest infestations are usually the result of poor growing conditions, poor soil and water management. But there are some severe, aggressive pests and diseases that infest and infect plants no matter how good the growing conditions. And there are many instances of insect pests killing trees outright, or usually in combination with other negative factors. 

 

In the absence of an informed pest control program and spray equipment, the best approach to prevention is a comprehensive plant health care program that includes soil organic matter building (easiest is to mulch, mulch and more mulch); adequate irrigation during dry season and consider fertilization. 

 

 

[drtreelove]

As much as I respect Samui Jimmie's experience and positive contribution to this forum, I don't really agree with this statement:  "I would say trees have survived millions of years, rarely will insects kill a tree... let nature take care of itself... "  

13,000 posts, he may not get outside much. Just kidding Jimmy  

 

For plants in a natural, evolved, undisturbed ecosystem this may be the case. But where does that exist anymore in the world that humans dominate? With altered environments that mankind creates, development, agriculture, pollution, depleted soils,  world travel and transporting of exotic plant materials, etc, there are many extremes that create ideal conditions for extreme pest problems. That, and environmental extremes like drought can set up killer plant pest and disease situations. 

 

Millions of pine trees are being killed by pine bark beetles here in the western United States, due to the predisposing factor of extreme drought stress. 

 

The coconut hispid beetle made it's way west from Viet Nam and has devastated the coconut plantations in Ko Kut (where I saw for myself thousands of dead palms and a ruined industry) and other areas of Thailand. Samui and other high value coconut markets have been somewhat saved by the Ag Dept Biological Control Division importing and release of a mini wasp parasitoid. But their budget and effectiveness is limited. 

 

The exotic pathogen causing sudden oak death syndrome and massive oak mortality in California was initiated by importing of infected plant materials for landscaping. 

 

Development of residential properties in Thailand often uses imported clayey subsoil for landscape fill, which is extremely deficient in essential soil minerals, organic matter content and biological activity. This depleted growing medium is a prescription for facilitating plant problems. 

 

Harsh chemical fertilizers and pesticides contribute to the degradation of soil biology and beneficial pest predators and parasitoids. 

 

If growing conditions are improved with good soil and water management, then plants can build some degree of natural resistance to pests and diseases. 

 

 

[Anthony5]

45 minutes ago, drtreelove said:

As much as I respect Samui Jimmie's experience and positive contribution to this forum, I don't really agree with this statement:  "I would say trees have survived millions of years, rarely will insects kill a tree... let nature take care of itself... "  

13,000 posts, he may not get outside much. Just kidding Jimmy  

 

For plants in a natural, evolved, undisturbed ecosystem this may be the case. But where does that exist anymore in the world that humans dominate? With altered environments that mankind creates, development, agriculture, pollution, depleted soils,  world travel and transporting of exotic plant materials, etc, there are many extremes that create ideal conditions for extreme pest problems. That, and environmental extremes like drought can set up killer plant pest and disease situations. 

 

Millions of pine trees are being killed by pine bark beetles here in the western United States, due to the predisposing factor of extreme drought stress. 

 

The coconut hispid beetle made it's way west from Viet Nam and has devastated the coconut plantations in Ko Kut (where I saw for myself thousands of dead palms and a ruined industry) and other areas of Thailand. Samui and other high value coconut markets have been somewhat saved by the Ag Dept Biological Control Division importing and release of a mini wasp parasitoid. But their budget and effectiveness is limited. 

 

The exotic pathogen causing sudden oak death syndrome and massive oak mortality in California was initiated by importing of infected plant materials for landscaping. 

 

Development of residential properties in Thailand often uses imported clayey subsoil for landscape fill, which is extremely deficient in essential soil minerals, organic matter content and biological activity. This depleted growing medium is a prescription for facilitating plant problems. 

 

Harsh chemical fertilizers and pesticides contribute to the degradation of soil biology and beneficial pest predators and parasitoids. 

 

If growing conditions are improved with good soil and water management, then plants can build some degree of natural resistance to pests and diseases. 

 

 

 

 

Have to agree 100%. I live surrounded by palm trees, and this year I can see dead trees as far as I can look. Was driving around today about 10 km from where I live and noticed a complete palm plantation that was dead.

[Anythingleft?]

On 8/30/2016 at 3:40 PM, bubba45 said:

My question is, can I just wait these out

If someone said no how exactly would you go about removing the buggers?

[chiang mai]

About three months ago one of our trees was hit with an infestation of caterpillars although they were not at all like the ones in the OP, the infestation was in one particular tree and others nearby were left untouched. They completely denuded the tree, not a single leaf remained, afterwards they all headed for the white walls of our house and proceeded to climb up the walls as far as possible, thousands of them over a two week period and the  birds had a feast. Everything went quite for a few days and then hundreds of butterflies appeared, a most welcome sight, eventually life returned to normal and the tree in question grew new leaves. All quite bizarre really but interesting to watch over time.

[samuijimmy]

Yes perhaps I was a little too general, in my response... there are off course some insects that will cause death to some trees... Coconut red beetle for example, has certainly done it's fair share.... but now seems to be in control ...

 

Thanks Dr Treelove for your additional information and help! 

[drtreelove]

2 hours ago, Anythingleft? said:

If someone said no how exactly would you go about removing the buggers?

 

First try to get information on the exact nature of the infestation and determine if it is really necessary to act with chemical or botanical insecticides. And evaluate the equipment available and understanding you have on mixing and applying pesticides. 

 

1. If you can anticipate the infestation (previous years timing experience), and if you know the 4 stages of complete metamorphosis in the moth life cycle (adult, eggs, larvae/caterpillars, pupae) then a preventive approach would be to spray the foliar canopy with horticultural oil at egg stage to smother the eggs. Late stage egg cycle with hatch in progress, and you could tank mix insecticidal soap or a botanical insecticide that would kill any young larvae that have already hatched, before massive feeding in later instars of caterpillar cycle. Very early preventive treatment could include a spray program with Neem oil (reproductive disruptor) or other botanical repellent insecticide (aromatic rosemary, thyme, clove oil), to prevent adult moth egg laying. 

2. If you don't anticipate for early preventive treatment, but are monitoring your tree and see early stage of caterpillar feeding (which is sometimes hard to see without sampling foliage for close inspection) then you can spray with Bt (Bacillis thuringiensis, a bacterial biological control that the caterpillars have to injest through feeding). Or use a contact insecticide for knock down of actively feeding caterpillars (insecticidal soap and/or a botanical insecticide like pyrethrins, or a synthetic pyrethroid like permethrin or cypermethrin). 

3. When the caterpillars have fed out and are descending to find habitat for pupation, is when they are most noticeable like in the photos of all the larvae on the tree trunk. By then it is just nuisance and not much help to the tree to spray. But you can use the knock down contact spray to kill the mature caterpillars and limit the nuisance and numbers going into pupa stage for the next adult moth emergence. 

 

If you don't have a tank sprayer or backpack sprayer that will reach the entire tree canopy, then preventive stem injection or soil drench with a systemic insecticide can be considered. Stem injection takes special equipment, but soil drenching is easy and practical. This method allows uptake by the root system and translocation throughout the foliar canopy gets the insecticide into the tree tissues so that anything feeding on the tree will ingest the poison.  But this is obviously not appropriate for food producing plants. And some systemic insecticides can end up in flowers and nectar and affect pollinators (bees). So use with discretion and good timing when flowering cycle is past. 

 

Or live with the nuisance and defoliation if not too extreme, aesthetically or economically unacceptable to you.