University of Maryland Extension

Pests and Diseases

No diseases were noted in any plants. Two-month seedlings, were predated upon by Three-lined lema beetle (Lema trilineata) (Figure 1).

This was a major pest throughout the summer. In 2016, hornworm became a major problem by mid-August, through the fall was so in 2017 (Figure 2). The Lema beetle provides an interesting management problem because it needs to be controlled during flowering, preventing use of carbaryl (SevinTM )   or other effective beetle insecticides. P. peruviana was greatly effected by this insect pest. However, P. pruinosa was resistant to Lema Beetle due to growth rate, but may still be a management problem when plant is young.

Spinosad products (like EntrustTM), labeled for ground cherries, are effective for caterpillars and Lema Beetle but must be applied in the evening when pollinators are inactive. 

Other lepidopteran species were found. Early during development, many P. peruviana husks were found to have holes and fruit eaten inside by an unidentified moth (Figure 3). This was a common occurrence in both 2016 and 2017.

By August 2017, wide spread infection of Pythium and Fusarium caused major collapse of more than half of the plants in the high-tunnel ending the study.

Table 1 is the pesticide spray schedule for the 2017 trials.

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