Questions About Tank Mixing Pesticides in Tobacco

— Written By Hannah Burrack
en Español / em Português
Español

El inglés es el idioma de control de esta página. En la medida en que haya algún conflicto entre la traducción al inglés y la traducción, el inglés prevalece.

Al hacer clic en el enlace de traducción se activa un servicio de traducción gratuito para convertir la página al español. Al igual que con cualquier traducción por Internet, la conversión no es sensible al contexto y puede que no traduzca el texto en su significado original. NC State Extension no garantiza la exactitud del texto traducido. Por favor, tenga en cuenta que algunas aplicaciones y/o servicios pueden no funcionar como se espera cuando se traducen.


Português

Inglês é o idioma de controle desta página. Na medida que haja algum conflito entre o texto original em Inglês e a tradução, o Inglês prevalece.

Ao clicar no link de tradução, um serviço gratuito de tradução será ativado para converter a página para o Português. Como em qualquer tradução pela internet, a conversão não é sensivel ao contexto e pode não ocorrer a tradução para o significado orginal. O serviço de Extensão da Carolina do Norte (NC State Extension) não garante a exatidão do texto traduzido. Por favor, observe que algumas funções ou serviços podem não funcionar como esperado após a tradução.


English

English is the controlling language of this page. To the extent there is any conflict between the English text and the translation, English controls.

Clicking on the translation link activates a free translation service to convert the page to Spanish. As with any Internet translation, the conversion is not context-sensitive and may not translate the text to its original meaning. NC State Extension does not guarantee the accuracy of the translated text. Please note that some applications and/or services may not function as expected when translated.

Collapse ▲

This week, I have received several questions about possible phytotoxcity associated with insecticide applications directed against tobacco budworm. The three seperate phone calls and emails each involved a different insecticide (all caterpillar materials), and  different application methods.

Yellowed tobacco following an insecticide application for tobacco budworm. Hertford County, NC. Photo via Matthew Vanv

Yellowed tobacco following an insecticide application for tobacco budworm. Hertford County, NC. Photo via Matthew Vann

In one case, the grower had used insecticide alone and seen yellowing. In two other cases, growers had tank mixed insecticides with fungicides. I am on the record as not recommending tank mixing insecticides with other pesticides, including fungicides or sucker control materials for two very important reasons:

1. We do not want to apply insecticides to the same part of the plant as we do fungicides or sucker control.

Insecticides to manage tobacco budworms should be applied as a directed spray into the bud, ideally in between 15 to 30 gpa water. In the early season, fungicides, if necessary, should be applied to acheive good coverage on leaves to target foliar pathogens. Sucker controls, on the other hand, should be applied to acheive goodstalk  run down. Although it might be temping to mix insecticides in early contact treatment to target tobacco budworm, treating budworms close (within 1-2 weeks) to topping does not make economic sense as the plant parts that budworms are feeding on will be removed when plants are topped. Post topping, insecticides for tobacco flea beetle and tobacco/tomato hornworms should be applied to leaves, not stalks. Therefore, tank mixing insecticides for these pests with sucker control materials will not result in good control. Growers often say that tank mixing “saves them a trip across the field”, but if the materials are not applied in a way to acheive good control, they haven’t saved a trip, they might have simply added the cost of an insecticide! Growers may also feel that some insecticides are “cheap”, so adding them to another material doesn’t cost much even if control is not optimum. Some insecticides may be less expensive, but they are not free! There is still an added cost that may not be justified by insect control or by yield benefits.

2. Tank mixing may impact efficacy and plant impacts.

Because I do not recommend tank mixing insecticides with other pesticides in tobacco, I do not compare the effects of insecticides when tank mixed in my research plots. Therefore, I cannot say if insect control will be same when materials are tank mixed, nor can I say if there will be compatibility issues.

So, what caused the yellowing on the plants pictured above and at the other two sites? We have not seen phytotoxicity (yellowing, burning, flecking) associated with any of the insecticides labeled for tobacco budworm in the last five years. However, with the wet, hot conditions of the last two weeks, tobacco leaves are very succulent, and any sprayed on materials may result in some visible leaf effects if it doesn’t evaporate quickly. This should be transient and is not a concern for yield. Other issues (contamination, for example) can also cause injury like that above and should also be ruled out.

Written By

Hannah Burrack, N.C. Cooperative ExtensionDr. Hannah BurrackProfessor & Extension Specialist and Director of Education & Outreach, NC PSI Call Dr. Hannah Email Dr. Hannah Entomology & Plant Pathology
NC State Extension, NC State University
Posted on Jun 13, 2013
Was the information on this page helpful? Yes check No close
Scannable QR Code to Access Electronic Version