When Should You End Insecticide Sprays for Tarnished Plant Bugs in Cotton?

— Written By
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 ▲

Article by Reisig and Collins

To answer this question, you need to know when the field first reached cutout, which is at 4 nodes above the first position white flower. Keep in mind that the last effective bloom date (the point at which there is a 50% chance the bloom will set a harvestable boll) for North Carolina is generally between August 20 – 25, but can range from August 15 – September 1 depending on fall weather and location within our state. So generally, any squares that have not bloomed by this point are likely not going to matter significantly for yield. Even if they do make it to harvest they will likely contribute little to overall yield if the bottom and middle crop is good. Please consider this before investing in the cost of an insecticide application that may not be 100% effective (see insecticide trial results below).

Plant bug management after cutout really needs to focus on keeping the internal boll injury to a minimum. Like stink bugs, plant bugs can feed on bolls and, like stink bugs, plant bugs transmit pathogens that can stain lint or cause boll rot and they can interfere with locule development. Occasionally bolls can abscise from plant bug feeding. While most stink bugs in cotton (brown and green) prefer to feed on medium (just under an inch in diameter) and small bolls (~1/2 inch diameter), plant bugs prefer to feed on small bolls. Internal boll injury from stink bugs and plant bugs is indistinguishable, so it is important to scout!

Bolls are safe from plant bug feeding once they accumulate 300 DD60s. During this time of the year, we typically accumulate around 18 DD60s a day. So it takes around 17 days for a boll to be completely safe from plant bugs. More recent data from the Midsouth suggest that once cutout is reached a boll is safe from tarnished plant bugs once it accumulates 250 DD60s, or around two weeks. Therefore, only bolls that formed before August 25 should be protected from tarnished plant bugs, and they should only be protected for two weeks following cutout. Scott Stewart, University of Tennessee, recommends increasing the threshold from 2-3 plant bugs per drop cloth sample to 3-5 plant bugs per drop cloth sample after cutout. Both stink bugs and bollworm should be managed until bolls reach 350 DD60s.

Be sure to rotate insecticides, especially if you’ve used multiple sprays. Results from some previous plant bug insecticide trials can be found on the Insecticide Recommendations for Plant Bugs page and results from this year’s trial are below.

First treatment chart image

Please note that the labeled rate for Bidrin and plant bugs is 4-8 oz and only 3.2 oz was used in this trial.

Second treatment chart image

Please note that the labeled rate for Bidrin and plant bugs is 4-8 oz and only 3.2 oz was used for the first application. Second application is denoted by fb (fb= followed by) and was made seven days after the first application.