What Is Wrong With My Blue Fox Tail Agave?

Are there any tan to brown sunken lesions on leaves, lesions are merging to girdle stems and petioles?

Are there any reddish-brown streaks on the outer and inner bark, as well as gum or dark sap oozing from the diseased area?

Are the seedlings dying and the stems are girdled or rotted at soil line?

Are there any small, pencil-sized holes towards the base of leaves, plants may be wilting accompanied by a putrid odor?

Are the leaves covered with small bumps?

Do the leaves have large, ragged holes in them?

These symptoms indicate a fungal disease - Anthracnose. Avoid stressing plants by providing them with adequate irrigation and fertilization. Avoid damaging plants and creating wounds for pathogens to enter. Prune out dead or dying limbs to reduce levels of disease inoculum.

These symptoms indicate fungal disease Phytophthora Root and Crown Rot. Phytophthora pathogens are favored by wet conditions, and the risk of disease can be reduced with good water management. The disease tends to affect plants in poorly drained areas, where susceptible plants are surrounded by standing water or saturated soil for prolonged periods of time. Provide adequate drainage and know the water needs of individual plants.

If your seedlings are falling over and the stems are girdled or rotted at the soil line, the most likely cause is a damping-off disease. Remove and destroy all infected plants. To prevent damping-off let the soil surface dry between waterings, thin seedlings to avoid overcrowding, and do not add nitrogen fertilizers until plants have developed leaves.

Female Agave snout weevils chew into the plant base, where they lay their eggs and infect the plant with a species of Erwinia bacteria. Hatched larvae feed on the rotting plant material. The bacterial infection is what actually causes the most damage; it induces wilting, accompanied by a putrid odor, and may cause the plant to collapse and die. Remove all infected plant parts from the area and search surrounding soil for adult weevils or larvae. Preventative pesticides are available where snout weevil infestations are known to occur; these can be applied around the base of the plant in early April and late May.

Leaves covered by small bumps are caused by scales. These tiny, shelled insects often feed on the undersides of the leaves, causing an unhealthy appearance with yellowish blotches on the upper leaf surfaces. Scrape off minor infestations with your fingernail. Prune out badly infested growth, or use a soft brush and soapy water to gently scrub the scales off the stems. Control scales by spraying insecticidal oil during the growing season.

Large, ragged holes in the leaves are caused by slugs and snails. Slugs and snails feed on the plant leaves usually at night. To control slugs and snails use diatomaceous earth around your plants. You can also handpick them during the night or use shallow dishes filled with beer as a trap.

If the leaves are covered with white, cottony clusters the culprits are mealybugs. These tiny insects are covered with a fluffy white coating. They feed by sucking plants sap. They produce the sticky substance honeydew which makes leaves sticky. You can control them by washing them off the plant with water spray. Insecticidal soap should be used with severe infestations.