Spider Mites

• Spider mites are a common pest of many ornamental shrubs, trees and flowers. Marigolds are often attacked by this tiny member of the spider family. Spider mites are usually red, green or brown and are very difficult to see with the naked eye. This pest feeds on the undersides of marigold leaves, causing the leaves to appear stippled, yellow and the entire plant may become stunted. A fine, silky webbing on the surface of marigolds is a sign of heavy mite infestation.
  
  

Spider Mite Control

• Spraying your marigolds with a hard stream of water twice each week, can help control spider mites. This process is known as syringing, which removes mites by knocking them from host plants with forceful jets of water. Horticultural soaps and oils are another way to control spider mites. These products work by covering the air holes of the mite, causing it to smother. Miticides are available for heavy infestations of spider mites and are contact chemical products. This means that you must cover the entire plant with the miticide to eliminate spider mites.
  
  

Grasshoppers

• Grasshoppers are a damaging pest of many flowers, including marigolds. This insect has chewing mouthparts, used to feed on the host plant. Many grasshoppers are quite large, measuring up to 2 inches in length. Grasshoppers have large hindlegs that aid them in jumping great distances. This pest damages marigolds by chewing on its leaves and flowers. Large populations of grasshoppers can cause serious damage to marigolds, causing them to become unsightly.
  
  

Grasshopper Control

• There are several natural predatory insects that feed on grasshoppers, keeping them under control in many areas. Parasitic wasps, lacewigs and lady beetles all feed on grasshoppers. Birds also feed on grasshoppers, helping keep their numbers low. Homeowners who have heavy infestations of grasshoppers, may wish to use chemical control methods. There are many types of chemical control methods available for grasshopper control at your local garden center. However, using chemical control methods may result in the death of natural predatory insects that help keep grasshoppers under control.