What are these nasty caterpillars?

[KawDang]

These slug-like bright yellow caterpillars are decimating my Thai olive trees (nothing else).

Sorry the snap is blurry.

Can anyone tell me their name and an organic way of putting them to the sword?

Sent from my iPhone using Thaivisa Connect Thailand

[soidog2]

Can't tell from the picture but you should spray immediately either with an organic neem (sadaw) based solution; slow but works in a couple of weeks.

Or with a Cypermethrin/Abamectin solution; fast, it will save your leaves now,

[gwynt]

This chemica does not look to be an organic fix sounds highly toxic

Cypermethrin is highly toxic to fish (6).

• Some products for agricultural and commercial

outdoor applications are limited to use by Certified

Applicators (6). Such products bear specific

precautions and directions to avoid contamination of

water (6).

And this one don't seem to be much better

Abamectin

Restrictions:

o Do not apply by air.

o Follow label instructions for frequency and number of applications per year or crop.

o Do not apply through irrigation systems.

o Do not apply within 35 metres upwind of aquatic areas or when wind speed is above 13

kph. Do not use during a temperature inversion.

o It is a violation of the Pest Control Products Act to use this product in a manner

inconsistent with its labeling. REFER TO LABEL FOR SPECIFIC RESTRICTIONS.

Think I would stick to Neem. and introduce some Guinea Fowl as patroling guards, they eat insects without cousing too much damage to the plants.

[drtreelove]

Gwynt is right, KawDang did ask for an 'organic' solution. Soi Dog has offered some very effective pesticide choices and other than the neem, they are considered low toxicity for mammals, but not organic program compatible. The Abemectin should not be used with food producing plants.

Cypermethrin is a pyrethroid, a synthetic chemical version of pyrethrin, the old standard botanical extract from a chrysanthemum flower. The botanical pyrethrin would be considered as organic program compatible, because it bio-degrades in sunlight within 12-24 hours. It offers the same immediate knock down effect on caterpillars, but without the residual effectiveness or extended possible harm to beneficial, predatory insects as the pyrethroid. I use pyrethrin for oak moth caterpillar control here in California, and the caterpillars fall out of the tree when I spray, before I can get out of the way. I don't know a Thai product name, sorry. Maybe someone else can help. Note: piperonyl butoxide is a common activator ingredient in in pyrethrin products. It increases effectiveness but would not fit the "organic" category. So if you are strictly organic, look for a pyrethrin product without PB. You may have to spray twice. Pyrethrin and pyrethroids are not systemic, meaning they are not mobile in the plant tissues and therefore don't translocate into the flowers and fruit.

Abemectin is a wider range pesticide that kills mites as well as insect pests. (Pyrethroids do not.) It is a systemic pesticide, so is not compatible with edible/food crops. For non-edibles, Abemectin will also offer immediate contact knock down, but may be 'over-kill' for caterpillars. And it is a step up in mammalian toxicity and harm to beneficials, most products are rated as 'Warning' label by US EPA, as opposed to the lower toxicity rating of 'Caution' for most pyrethroids. ('Danger' is the highest). I sometimes use Abemectin in closed system tree stem injections, to be taken up internally in the sap flow and not sprayed on the foliar canopy, to reduce environmental contamination. (systemic pesticides are not compatible with food crops, organic or not)

The reason that neem products may take a little longer to provide effectiveness, is that Azadirachtin (the primary active pesticidal ingredient in neem oil) is not really a contact insecticide, it is a repellent, anti-feedant and reproductive disruptor. So it is better used for prevention and not for immediate control of an advanced pest infestation. To use it effectively, try and anticipate possible pest activity (get to know your plant/crop, pests and timing), then start spraying your neem seed oil product before onset of infestation and weekly during active cycle.

Other 'organic' methods for caterpillar control are:

manual (if the plants are small you can pick them off by hand, maybe with a cotton glove on), or use a water jet to knock them off

insecticidal soap (tricky because it can burn some plants, especially in high temperature conditions. And it can burn the applicator's eyes).

Preventive maintenance methods:

Don't over-fertilize, as high nitrogen fertilizer, including manures, creates excessive vegetative growth and high sugar content which is attractive to some pests.

Build plant resistance to pest and disease problems with soil and water management. This should include appropriate irrigation (avoid drought stress); improve soil fertility, weed suppression and soil moisture retention with organic matter, mulch, soil minerals. www.soilminerals.com

Hope that helps, Don

[gwynt]

Here is another suggestion.

http://homeguides.sfgate.com/garlic-spray-garden-pests-22908.html

If the link don't work copy the address and paste