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Dick Grimshaw (Dickji)
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Username: Dickji

Post Number: 266
Registered: 05-2002
Posted on Wednesday, June 29, 2005 - 04:17 pm:   Edit PostDelete PostView Post/Check IPPrint Post   Move Post (Moderator/Admin Only)

Here follows a note from Prof. Johnnie van den Berg of South Africa about the use of vetiver as a trap crop for stem borer.

Quote
The local vetiver work is doing very good. Large scale field experiments showed that vetiver really does work as trap crop for Chilo partellus under field conditions. Other field work showed that the vetiver barrier around the maize acts as a reservoir for beneficial insects that attack crop pests in maize. We observed a move of beneficial insects (predators and parasites of pests) from maize towards vetiver when it became winter and the maize crop died. We are now waiting for spring to monitor if and when they move back. We will then be able to see if vetiver can be said to be a reservoir and refuge for beneficial insects.

We have done many surveys and samples here and have not come across any pests of vetiver. One unidentified stem borer was found where vetiver was used for soil stabilization in a mountain pass but it was not important.

We are going to survey in the Eastern Cape province in Mid July where they use vetiver to limit soil erosion in Pine apple fields.
I will keep you updated.

Bye
Johnnie

Unquote

Prof. Johnnie van den Berg
School of Environmental Sciences and Development
North West University (Potchefstroom Campus)
Private Bag X6001
Potchefstroom
2520
SOUTH AFRICA
Tel: +27-18-299 2376
Fax: +27-18-299 2370
 

Dick Grimshaw (Dickji)
Board Administrator
Username: Dickji

Post Number: 235
Registered: 05-2002
Posted on Tuesday, July 06, 2004 - 04:31 pm:   Edit PostDelete PostView Post/Check IPPrint Post   Move Post (Moderator/Admin Only)

Vetiver and Insect Control

An earlier posting summarised some results from Dereck Jakobi of Zambia, organics@zamnet.zm. Here is another note from Dereck sent to me recently. Interestingly Dereck farms 200 ha of commercially produced organic horticultural crops. He sees the potential for vetiver in both erosion and insect control.

“We have noted the control of maize stalkborer in fields of Baby Corn as well as control of leafminers in peas as well as in our coffee blocks. The maize stalkborer control is more that the vetiver acts as a trap crop for the stalkborer moth when it lays its eggs, whereas with the leafminer it seems that the beneficial wasp population takes care of the leafminers.

I will be doing a lot more work on vetiver this coming season and hope to have more results later in the year. One of the things that I have noticed is that the fields should not be too large otherwise the beneficials become too diluted over the area. If the fields are contoured then planting the contours with vetiver would be excellent, this would serve a dual function,
stabilizing the field against erosion as well as providing the trap crop and beneficial habitat.

Being a farmer and not a researcher it is often very difficult to quantify my findings, however I think the only justification I need for myself is that I see it working. There is a Prof. Johnnie van der Berg of the University of Potchestroom in South Africa who I have been sharing findings with also. I am involved mainly in export horticulture and coffee production so have been looking at areas where this industry can use vetiver”.

Coffee farmers,especially in Central and South America might find this article interesting.
 

octavio torres jimenez (Ambyagro)
New member
Username: Ambyagro

Post Number: 5
Registered: 02-2003
Posted on Wednesday, February 18, 2004 - 05:03 am:   Edit PostDelete PostView Post/Check IPPrint Post   Move Post (Moderator/Admin Only)

Heliothis, Spodoptera and Stink bugs(Pentatomidae and Reduvidae) attacks tomato fruits. Bugs attacks,however, reaches economical damages. Others two insects, no
In crops without vetiver three insects are highly dangeorus
 

Dick Grimshaw (Dickji)
Board Administrator
Username: Dickji

Post Number: 229
Registered: 05-2002
Posted on Saturday, February 14, 2004 - 08:21 pm:   Edit PostDelete PostView Post/Check IPPrint Post   Move Post (Moderator/Admin Only)

Ocatvio,

can you expand (tell us more) on your statement "However bugs attacks seems to be significant. "

dick
 

octavio torres jimenez (Ambyagro)
New member
Username: Ambyagro

Post Number: 4
Registered: 02-2003
Posted on Saturday, February 14, 2004 - 04:00 am:   Edit PostDelete PostView Post/Check IPPrint Post   Move Post (Moderator/Admin Only)

In Colombia North Coast I grow tomatoes adajacent and inside vetiver nurseries. Heliothis/Spodoptera attacks over tomatoes are minimun. However bugs attacks seems to be significant. Is necessary a major observation
 

Dick Grimshaw (Dickji)
Board Administrator
Username: Dickji

Post Number: 226
Registered: 05-2002
Posted on Tuesday, February 10, 2004 - 01:22 am:   Edit PostDelete PostView Post/Check IPPrint Post   Move Post (Moderator/Admin Only)

The Southern Africa Vetiver Network reports via a letter from Dereck Jakobi of Zambia (email: organics@zamnet.zm) who manages 200 ha of organic farms. Thus far he has found that baby corn grown in conjunction with vetiver hedgerows shows significant reductions in stem borer damage. They have now experienced even better results with the reduction of leaf miner incidence on coffee and peas. The kill rate in coffee was almost 100%, and in the peas out of a sample of 50 infected leaves they found only 2 live leaf miners. They have deliberately not sprayed the peas so as to allow the leaf minor population to build up, but there appears to be no economic damage to the crop. They are encouraged by the results and are now looking to establish major hedgerows on all their company production units.

If you want more information on this subject I suggest that you contact Dereck directly
 

Dick Grimshaw (Dickji)
Board Administrator
Username: Dickji

Post Number: 200
Registered: 05-2002
Posted on Tuesday, October 14, 2003 - 11:45 pm:   Edit PostDelete PostView Post/Check IPPrint Post   Move Post (Moderator/Admin Only)

The note from El Salvador is from Javier Frances
of NOBS:

email: "Nobs Hidrodifusion SA de CV" <nobs@navegante.com.sv>
 

Dick Grimshaw (Dickji)
Board Administrator
Username: Dickji

Post Number: 199
Registered: 05-2002
Posted on Tuesday, October 14, 2003 - 11:39 pm:   Edit PostDelete PostView Post/Check IPPrint Post   Move Post (Moderator/Admin Only)

We have a plantation (in El Slavadore) of Vetiveria Zizanioides next to a sugar cane plantation and we have seen that the borer rather lay his eggs on the vetiver that in the sugar cane. On the other hand the sugar cane seems to be healthy with very little attack of the insects compared with other cane plantations that do not have vetiver on the side.

We have also done much work with small farmers that grow "corn" and we have never had complains about insects. I will pay more attention to the attack of the borer to corn also.
 

Dick Grimshaw (Dickji)
Board Administrator
Username: Dickji

Post Number: 198
Registered: 05-2002
Posted on Sunday, October 12, 2003 - 11:42 pm:   Edit PostDelete PostView Post/Check IPPrint Post   Move Post (Moderator/Admin Only)

Van den Berg, J., Midega, C., Leswifi, M.C.,
Fourie, D. & Wadhams, L.J. paper:

Can Vetiver grass, Vetiveria zizanioides, be used to manage insect pests? is excellent and should be read by all agronomists working in tropical countries.See
application/pdfStem borer and Vetiver
ICV3_stem borer.pdf (274.6 k)


Vetiver hedgerows significantly reduce the amount of stem borer damage to maize and other cereal crops due to the fact that stem borers lay their eggs preferably on vetiver leaves. Due to the hairs on the underside of vetiver leaves the larvae cannot burrow into the vetiver and therefore fall off and die. Vetiver leaves are also hosts to insect predators that over winter on the plant, that then attack other insects on the maize in the spring.

Stem borer - Chilo species - is also a problem for rice and sorghum. I would urge all field staff to test the effectiveness of vetiver for stem borer control on all creal crops as soon as possible. If confirmed that vetiver is doing the job as a insect trap, then we have an important tool to persuade farmers to use vetiver on their fields for both soil and water conservation and insect control and management. Vetiver would be an Integrated Pest Management tool with a difference!

Remember also that if cut reguarly vetiver leaves provide excellent forage and also makes a good mulch that is reported to control whitefly. What a plant!!!

Johnnie Van den Bergen can be contacted at: "Johnnie v/d Berg" <johnnie@igg2.agric.za>. He is happy to advise and help you
 

Dick Grimshaw (Admin)
Posted on Tuesday, January 15, 2002 - 08:27 pm:   Edit PostDelete PostView Post/Check IPPrint Post   Move Post (Moderator/Admin Only)

An old document from Louisiana discusses the use of vetiver as a pesticide when mulched (Vetivert Essential Oil Corp. Early 1900s):

"There are many plants, minerals, and other nature products in this universe, that more or less protect the human race against the bothersome insects of life. It seems that the insect life has an absolute distaste for vetivert. We have found in the growing of this plant that no insects of any kind ever came near it. We also find that in the powdered form, the tops mixed with the residue of the oil repel any and all insects. It is for that reason, so important that this plant be given every consideration and not be allowed to grow wild as heretofore has been the case in this country. It is as necessary to have vetivert as it is to have salt in your food.

Strawberries that were grown in the Southland have been more or less contaminated by insects, and although pine needles and other things have been used to safeguard against these pests of nature, a great loss was wrought against the strawberry crop. We have found from experimental work that the tops of vetivert, in the same formation of mixture with the residue of the roots, will make an absolute repellent for the insects that may hurt the crop.

A few years later, Harold Levey wrote of vetiver in Louisiana (Levey 1940):

An interesting fact observed in connection with the growing of the vetiver plant in close proximity to the other crop which originally emanated from India, viz., sugar cane, is that the vetiver inhibited to a very substantial degree the attack upon the sugar cane of certain entomological organisms such as the cane borer. This procedure was used to a limited extent some years ago, but has no longer become necessary in view of the fact that the newer types of sugar canes originally cultivated in Java are now practically immune from such attacks by their very nature."

Current work in South africa is beng undertaken to test whether vetiver grass hedgerows will reduce stem borer in adjacent maize crops. I wonder whether it might do the same for rice, if so it would be a very useful crop to both stabilize paddy field bunds and reduce stem borer damage to rice. I do remember on a visit to China in 1990 it was reported that in Fujian Province Vetiver grass adjacent to rice was infested with stem borer, the Chinese were concerned that it might be an alternative host, where as in fact it might have been providing protection. South African laboratory trials show that the stem borer larvae that grow on the vetiver later die and do not therefore reach maturity.

This subject would be good for further investigation and discussion
 

Dick Grimshaw (Dickji)
Board Administrator
Username: Dickji

Post Number: 143
Registered: 05-2002
Posted on Friday, May 02, 2003 - 10:31 pm:   Edit PostDelete PostView Post/Check IPPrint Post   Move Post (Moderator/Admin Only)

Can Vetiver grass, Vetiveria zizanioides, be used to manage insect pests?

Van den Berg, J.1, Midega, C.2, Leswifi, M.C.3,
Fourie, D.3 & Wadhams, L.J.4
1School of Environmental Sciences, Potchefstroom University for Christian Higher Education, Private Bag X 6001, Potchefstroom, South Africa.
2International Center for Insect Physiology and Ecology,
P.O. Box 30772, Nairobi, Kenya
3ARC-Grain Crops Institute, Private Bag X1251, Potchefstroom, South Africa
4 Rothamsted Research, Harpenden, Herts, AL5 2JQ, United Kingdom

Abstract: In addition to its well known soil conservation properties, Vetiver grass, Vetiveria zizanioides, is also said to be repellent to many insect species. However, references to its repellent characteristics are largely anecdotal and, apart from recent research on Formosan termites, few scientific papers addressing this issue exist. Infestation of Vetiver by pests of other crops have been recorded and concerns raised about Vetiver grass being a refuge for insect pests. This paper addresses the benefits that Vetiver may have in control of these pests. Vetiver grass is highly preferred for oviposition by moths of the lepidopterous stem borer Chilo partellus, a serious pest of maize, rice and other grain crops in Asia and throughout East and Southern Africa, where it can cause yield losses of up to 58% in maize. These observations prompted more detailed research on stem borer/Vetiver grass interactions. Studies were therefore conducted to determine the relative oviposition preference of gravid female moths for Vetiver grass and maize, and to determine the suitability of Vetiver grass for larval survival. Two-choice preference bioassays were conducted in the laboratory and in the greenhouse. Larval survival was evaluated in greenhouse studies on plants growing in soil. Results showed that, although there was a highly significant oviposition preference compared to maize, larval survival was minimal. Thus, Vetiver has potential as a trap crop component of an overall ?push-pull? strategy to concentrate oviposition away from the maize crop and reduce subsequent population development.

Key words: Chilo sp., IPM, maize, push-pull, stemborers, habitat management.

FOR FULL PAPER ATTEND ICV3

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