Weeds

   Use an integrated approach to effectively manage weeds in cucumber production. The IPM program for weed control uses weed identification, monitoring, sanitation, alternative cultural practices, and timely herbicide treatments. The first approach for weed management is to avoid planting in fields that experience heavy weed infestations. A weed map for each field helps in the design of weed control measures and provides a record of weed problems.

   The benefits of proper field preparation can not be overemphasized to improve cucumber growth and minimize weed problems during the crop growth cycle. Even soil preparation, proper soil moisture, and a pre-plant fertilized field will improve stand establishment and early crop growth. Cultural control practices for weed control include shallow cultivation, plowing, disking, hoeing, crop rotation, cover cropping, living mulches, organic or plastic mulches, and herbicides. For effective weed control, herbicides need to be applied at the correct rate and time. Therefore carefully read label instructions to achieve maximum weed control with herbicide treatments. Surface-applied herbicides normally require rainfall or irrigation after application to maximize weed control efficiency. Cucumbers have a poor competitive ability against weeds, especially during the initial three weeks of growth. Weeds are normally controlled through a combination of cultural practices and herbicide treatments.

   Pesticide applications should be conducted carefully because the cucurbits are among the most sensitive vegetables to herbicides. For planting selection sites, avoid fields with infestations of troublesome weeds such as nutsedge and also of fields which have received applications of herbicides such as Atrazine which is likely to have unfavorable residual effects on cucumber growth. Herbicides which may cause injury in cucumber because of carryover include Atrazine, Lexone/Sencor, Bladex, Milogard, Princep, Surflan, Cotoran/Lanex, Karmex/Direx, Lorox/Linex, Classic, and Scepter. Laboratory tests are available to detect Atrazine levels in cucumber leaves with apparent symptoms of herbicide injury.

Successful weed control was obtained in Florida trials with a pre-emergence herbicide application and two hoeings after planting. One or two cultivations while cucumber plants are still young also may provide acceptable weed control. The two hoeings could be substituted with a post-emergence herbicide to achieve similar effectiveness in weed control. Growing cucumbers with plastic-mulch is an effective method of controlling weeds. Rows between the mulch beds can be treated with registered preemergence or postemergence herbicides for cucumbers, since the cucumber roots may extend into those treated areas. Grassy weeds of cucumbers in Hawaii include lovegrass, Eragostis pectinacea, sandbur, Cenchrus echinatus, and wiregrass, Eleusine indica. Broadleaf weeds include spiny amaranth, Amaranthus spinosus, spineless (smooth) amaranth, Amaranthus spp., Flora's paint brush (red pualele), Emilia sonchifolia, Orange pualele, Emilia coccinea, jamaica vervain (joee), Stachytarpheta jamaicensis, black nightsahde (popolo), Solanum nigrum, pigweed or purslane , Portulaca oleracea, richardia, Richardia scabra, sow thistle, Sonchus oleraceus, spanish needle, Bidens piolosa, garden spurge, Euphorbia glomerifera, swinecress, Coronopus didymus, and tarweed, Cuphea carthagenensis.