Black widow spider found

14 September 2001

Black widow spider found

A live female black widow spider was found yesterday by a Kaitaia woman in a bag of Californian Table Grapes she had brought at the supermarket.

A black widow spider’s bite is venomous. In case other black widow spiders may have arrived in New Zealand undetected, food retailers and consumers should remain vigilant.

The Ministry of Agriculture and Forestry has suspended imports of grapes from the export facility in California where the grapes were from until a full investigation of its treatment practices are undertaken by United States Department of Agriculture officials.

The treatment facility differs from the warehouse MAF suspended imports from last month when another black widow spider was found amongst grapes at a Fielding supermarket.

The result of the investigation last month established that the black widow find was due to deficiencies in the calculation of the fumigant treatment dosage. This has now been rectified.

Justin Downs, MAF’s national adviser, International Operations (Plant Imports) says MAF undertook inspections and audit activities to confirm that existing systems meet MAF standards. A failure was found and corrective action was taken. Importing has resumed from this facility.

“We have in place all reasonable checks available to us. However, as mandatory post-harvest treatment is only 90 percent efficient, interceptions of live spiders is always a possibility. Despite this the interception rate is very low. The only way to make sure nothing gets through is to stop importing table grapes all together,” he said.

New Zealand imports approximately 400,000 cartons of Californian table grapes a year.

The female black widow spider has an elongated black shiny body, with white and red markings on its side. The female’s abdomen is almost spherical, usually with a red hourglass mark on its back or tow red marks on its back. It may grow to the size of a 20-cent coin.

Although the black widow spider is not normally aggressive, it will bite to defend itself or its eggs. The spider’s bite is venomous. The effect of a bite may result in abdominal pain, breathing difficulties, nausea and vomiting. Full recovery can take up to 10 days. It is highly unlikely a healthy person would die as a result of a black widow spider bite however the very young, the very elderly or debilitated people are at greater risk.

If anyone suspects a black widow spider may have bitten them, they should place ice on the bite, and seek urgent medical attention. The injury is treated symptomatically. If the spider can be captured without endangering anybody, it should be caught to confirm its identification and the local public health service advised.

If anyone finds what may be a black widow spider they should approach with caution. Fly spray could be used to stun the spider to allow it to be killed and/or placed into a sealed jar.

For further information contact Gita Parsot, Senior Communications Adviser, MAF on 04-498-9806 or

Selina Gentry, Media Adviser, Ministry of Health on 04- 496-2483 or 025-277-5411

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