Peppers are a spicy, delicious vegetable, but a problem called Stip disorder which damages some pods is causing heartburn for some Southwestern producers and processors.

“Stip disorder is likely caused by a physiological disorder possibly combined with abiotic stress factors including hot temperatures,” says Mark Uchanski, vegetable physiologist with New Mexico State University (NMSU) in Las Cruces.

There are reports of Stip disorder as early as 1975 in Texas. The disorder was first reported and studied in California and Florida-grown peppers around 1995. The disorder was officially declared in New Mexico and Arizona chile pepper fields more recently.

Researchers and producers as far away as Australia and Israel have published studies describing the problem.

Uchanski used his speaking slot during the 2012 New Mexico Chile Conference in Las Cruces to issue the formal Stip disorder announcement to the attending 275 New Mexico and Arizona pepper growers, processors, and industry representatives.

Uchanski asked for a show of hands of those who had seen Stip-like symptoms on farms or at processing facilities. A few hands were raised. Uchanski then displayed a series of ugly Stip-infected chile photos in a PowerPoint visually illustrating the malady. He asked for another show of hands. More hands were elevated.

Chile peppers are a valuable cash commodity and New Mexico’s signature crop. In the state, Stip is more often found in green chile, infrequently in red chile, and so far not detected in paprika peppers.

“We don’t have exact numbers on financial losses due to Stip disorder in New Mexico and Arizona,” Uchanski told the group. “I have heard of pepper loads rejected at the processor due to this problem.”

Chile producers in New Mexico and Arizona have suspected Stip disorder since 2007 during the hotter summer months.

New Mexico is the nation’s top pungent chile pepper producer with 10,800 harvested acres; followed by California - 5,800 acres, Texas - 4,500 acres, and Arizona – 3,600 acres; all 2007 National Agricultural Statistics Service Census of Agriculture figures.

Initial visual signs of Stip include a hazy, orange-red area inside the pepper pod. Later symptoms include depressed, oval dark-brown or black spots (lesions) one-quarter to one-half inch in diameter. The lesions move toward the pod exterior. A cut open pod with Stip reveals a layer of dead cells.

“The interior of the infected pod interior appears smashed similar to an accordion,” Uchanski said. “It’s similar to when an apple is cut open and the fruit browns quickly - so does the chile pepper.”

Symptoms worsen during the ripening and post-harvest periods. The brown tissue rarely moves to the pod cuticle (waxy outer layer). Secondary decay organisms are absent in fresh pods. There are no foliar symptoms with the disorder.

Uchanski says microscopic analyses of infected pods have clusters of collapsed (dead) cells. The browning is caused by the release of tissue cell contents combined with oxidation. 

There is no sign of a puncture wound from insects or infection. The finger is sometimes pointed at stink bugs which Uchanski called a highly unlikely culprit.

California and Florida have gained a great deal of knowledge about Stip disorder since it was first found about 17 years ago.