Mexican Cypress (Cupressus lusitanica)

Pestalotiopsis is a group of fungi (now often placed in Neopestalotiopsis and related genera) that causes leaf spots and tip blight, especially on plants that are stressed or kept too wet. It shows up most after cool, rainy weather or in crowded plantings with poor airflow. Look for tan to dark-brown spots that may have a yellow edge, or shoot tips that brown and die back from the tip inward. Tiny black pinhead-like dots often appear in the dead tissue—these are the fungus’s spore-producing bodies. It commonly affects arborvitae, juniper, cypress, yew, boxwood, many palms (including indoor palms), and can also occur on strawberry leaves and fruit.

Fusarium wilt is a serious fungal disease caused by the soil-borne fungus Fusarium oxysporum. The fungus invades roots and blocks the water-conducting vessels (xylem) of the plant, causing progressive wilting and eventual death. Host-specific forms of the pathogen exist that attack different plant species.

Cercospora leaf spot is a common fungal disease caused by Cercospora species that affects many plant types, particularly beets, roses, and leafy vegetables. The disease thrives in warm, humid conditions and can cause significant defoliation, reducing plant vigor and yield. It spreads rapidly through water splash, wind, and contaminated tools.

Verticillium wilt is a soil-borne fungal disease caused primarily by the fungi Verticillium dahliae and V. albo-atrum. These pathogens infect plant roots and grow within the vascular tissues, blocking water and nutrient transport, resulting in wilting and eventual plant death. The disease affects over 350 plant species including vegetables, fruits, ornamental flowers, and trees. The fungi can survive in soil for more than 10 years as resistant structures called microsclerotia.

Spider mites are tiny arachnids (less than 1/20 inch long) related to spiders and ticks that feed on plant sap. They thrive in hot, dry conditions and can cause significant damage to ornamental and vegetable plants. During severe infestations, crop losses can reach 14% or higher as these pests disrupt vital plant processes including photosynthesis, carbon dioxide absorption, and transpiration.