Bacterial Wilt of Cucumbers

Identification and Control of Bacterial Wilt in Cucumbers

How Bacterial Wilt is Spread

Bacterial wilt of cucumbers is spread by Cucumber Beetles [1]. The bacteria survives in the digestive system of the striped cucumber beetle, even when the beetle is hibernating over winter.

When the beetles emerge in the spring and begin feeding they spread bacterial wilt via both the piercing mouths and fecal debris.

Once the bacterium enters the plant it rapidly multiplies and spreads. The bacteria does not attack the plant directly, but its rapid multiplication causes clusters and blockages within the plants vascular system resulting in wilting and dieing back.

Symptoms of Cucumber Bacterial Wilt

The unhealthy, weakened and wilting plant attracts more insects, including more cucumber beetles.

Leaves turn dull green, the foliage and finally the whole cucumber vine wilts and dies. When the stem is cut and squeezed a sticky, stringy ooze comes out.

Bacterial Wilt of Cucumbers is spread by Cucumber beetles

Once a cucumber plant is infected - it can't be saved - discard it, burn it , throw it in the trash - but never the compost, unless of course you'd like a re-occurrence next season.

Cucumber Beetles and larvae.

Control of Cucumber Bacterial Wilt

Control of bacterial wilt in cucumbers is done by controlling cucumber beetles. Cucumber beetle control should commence as soon your seeds or seedlings are in the ground.

The use of synthetic insecticides is not generally recommended. Esfenvalerate, a fairly new synthetic Pyrethoid is sometimes used, resistance is not well established. An older version known as fenvalerate. is sold under the trade names Conquer, Fenvastar, Shockwave, and Onslaught as well as several others.

Neem prevents the larvae from developing normally and is also a good alternative for later larval stages. [2] Neem degenerates rapidly in nature and need to be reapplied frequently.

Pyola is an effective alternative to chemicals. Made from canola oil and pyrethrins, pyola controls many stubborn insect pests, including the Colorado potato beetle and cucumber beetle.

Spinosad Spinosad Pesticide, an organic pesticide, is based on a bacterium 'Saccharopolyspora spinosa' , which was discovered in an old Caribbean rum still. It was discovered that these bacteria produce a substance that works as a neurotoxin in many insects. Susceptible insect species exposed to spinosad become 'intoxicated', stop eating immediately, and die within days.

'A laboratory bioassay of the spinosad formulation used in the field showed it had significant lethal effects on adults of both cucumber beetle species. Results indicated that the bait formulation used did not improve cucumber beetle control but may benefit from the addition of floral attractants or using a different type of cucurbitacin' [3].

Cheescloth tents or row covers are sometimes used to keep the beetles and other pests away from the plants.


1. Relationship Between Cucumber Beetle Density and Incidence of Bacterial Wilt of Cucurbits

2. Effects of Two Triterpenoids from Neem on Feeding by Cucumber Beetles

3. Evaluation of Cucurbitacin-Based Gustatory Stimulant to Facilitate Cucumber Beetle Management with Foliar Insecticides in Melons

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