From owner-drosophila@net.bio.net Wed Jan 03 22:00:00 1996 Path: biosci!ihnp4.ucsd.edu!swrinde!newsfeed.internetmci.com!uwm.edu!msunews!harbinger.cc.monash.edu.au!bunyip.cc.uq.oz.au!news.design.net.au!usenet From: Kurt Sepp Deifel Newsgroups: bionet.drosophila Subject: NEED HELP WITH PENDIMETHALIN {PROWL(R)} HERBICIDE IN LETTUCE Date: 4 Jan 1996 09:37:55 GMT Organization: Design OnLine, Toowoomba Lines: 115 Message-ID: <4cg75j$dp@bne2.design.net.au> NNTP-Posting-Host: tmba1.design.net.au Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 1.22 (Windows; I; 16bit) Please Help me, My name is Kurt Deifel and I am the Research and Development Officer for a large farming co-operative here in the Darling Downs in Queensland, Australia. The problem that we have at the moment is with the residual effect of pre-emergent selective herbicides in our Lettuce and Celery Transplants. The active constituent that we are having trouble with is Pendimethalin mixed in a Liquid Hydrocarbon Solvent. It is sold under the name of Prowl(R), Accotab(R), Go-Go-San(R), Herbdox(R), Sipaxol(R), Wax-up(R) and sold under Stomp 330E(R) here in Australia. It is manufactured by the American Cyanamid Company in the United States. The chemical belongs to the Dinitroaniline family and is originally a orange/yellow crystalline solid soluble in most organic solvents hence being mixed with the Liquid Hydrocarbon. The problem is that we have been using this product quite successfully to control certain weeds in our Lettuce and Celery for about 15 years and have had excellent results. Until last season when we started to find some abnormalities in our Lettuce resulting in this seasons Lettuce having catastrophic problems. Lettuce transplanted into blocks sprayed have very poor establishment figures ranging from 10-50% of the transplants dying. Once these Lettuce transplants had started to grow they soon became very uneven. With the plants appearing to be about two weeks different in the same blocks. Once they came to harvest only about 30-50% of the Lettuce could be harvested with the rest being either too small or not forming hearts. At first we thought that it was something else such as nutrition or insufficient irrigation but when we sprayed different blocks with different treatments then this soon told us the real story. Blocks that were not sprayed with this product had an excellent establishment, over 99.9% with about 60-70% of the Lettuce being harvested. Although this was still a disaster this was a large improvement on the blocks sprayed with Stomp 330E(R) with only 30-50% being harvested. We also applied another herbicide, active constituent Propyzamide or Pronamide under the trade name of Kerb WP(R) manufactured and released by Rohm and Haas Company. This appeared to have no effect on the establishment or growth, in fact it appeared to be better than the control where no herbicides were applied. There is such a large difference in the stunting that the rate of growth between a treated block and an untreated block is quite large, if you didn't know that they were both planted on the same day you would swear that there was 7 to 10 days difference in the two blocks. This results in the treated blocks being harvested almost two weeks later than the untreated block. All of these trials were replicated and the same results appeared pointing to the Pendimethalin being the problem. It appears that if applied this season to blocks it will result in killing plants and reduce yields by over 80%. And with the residual or background levels in the soil it will severely effect the growth and still result in massive reductions in yields. We have been applying the product according to the label and at the rate of 2.5 litres / hectare with the recommended rate being from 2 - 4 litres / hectare, and been more then generous with the minimum interval time and the 2-7 days required with holding period from spraying to transplanting. At the moment we are loosing $40,000 to $50,000 dollars Australian and will go broke very quickly if we cannot find a solution. If you know anything about this product or know anybody that might be able to help me please let me know. At the time being I would like to find out as much as possible but am very interested in knowing if; - I can take tissue and/or soil samples and send them to a laboratory to be analyzed to see if there has been any significant difference in the levels of Pendimethalin between the treatments and other farms or is the active constituent not translocated into the plant or does it simply effect the root system. - Do different varieties of Lettuce get effected differently by this problem. - Is there an indicator plant that I can use such as a grass species or other to tell us that concentrations are still toxic in the soil so we will know very roughly what level is in the field. I have read that some grass species are susceptible to this so that may work. - Is there any crop, element, chemical or technique that we can use to so called soak up or reduce the effects of the product in the ground, i.e. can I grow a certain crop species that will absorb the chemical in stolens or tubers or other plant part and use these to trap and store the product so we can dig this crop up and remove the Pendimethlin from the field. - Does this product have a history of having such a problem as remaining in the soil, does it have a long half life to break down or does it not break down, can I accelerate the natural breakdown process. - Could it be another product or product reacting with the Pendimethalin. Please help we with my quest for information and possible contacts, your time and knowledge will be greatly appreciated, and maybe I can even help you with some of your own problems. Please E-mail and post your reply so I can get answers as soon as possible because we have to try and find a solution very quickly. I will answer all letters. Thankyou very much in Reply, Regards Kurt Deifel -------------------------------------------------------------------- Mr. Kurt Sepp Deifel Research and Development Officer for Story Farms Pty. Ltd. E-mail address Snail Mail - F1/311 Bridge Street, Toowoomba, Queensland, 4350, Australia. Phone - (076) 361911 Fax - (076) 362216 .