Hemp Organic Integrated Pest Management (IPM); Thistles, Painted Lady Butterflies and Larvae

 Almost nothing can do as much damage to hemp plants and flower buds as caterpillars can. 

Painted Lady butterflies are attracted to aster-like wildflowers for use as host plants.

Most larvae go through a number of developmental changes (instars) during their transition from egg into butterfly form.  While in the caterpillar stages these larvae consume as much plant matter as they can and store the foraged protein for future use in egg production as mature butterflies.

There are quite a few caterpillars attracted to and often found on hemp plants.  Today I'd like to briefly talk about the Painted Lady Butterfly, Vanessa spp, butterflies and caterpillars.

Painted Lady caterpillars are often found growing and foraging in hemp leaves and hemp flower buds.  

Painted Lady butterflies will typically lay a single egg on a hemp leaf.  Once the egg hatches and the larvae begins to develop, a thread-like silky mesh will appear wrapped around two or more leaves as the caterpillar builds protective shelter.

Circular chew marks may appear of the edges of leaves as the larvae begin to feed.  In their early stages, the Painted Lady larvae may be light brown colored and spiny.  

During outbreak periods, a large number of Painted Lady caterpillars can significantly damage hemp plants with their voracious plant matter diets.  Not only can the Painted Lady caterpillars eat hemp plant biomass, but they can also (as with any other caterpillar and larvae) leave significant amounts of feces in hemp plant flower buds.  Hemp plant flower buds destined for edible product consumption may be seriously damaged or may even become a total loss.

Painted Lady butterflies and caterpillars serve an important role in our ecosystems however.  Even though they may be considered a pest to hemp cultivation efforts, Painted Lady butterflies should be accepted as a vital component of the ecosystem surrounding hemp cultivation operations.

The key to controlling Painted Lady crop damage lies not in eradication, but in supporting a balanced matrix of insect role within the overall surrounding ecosystem.  Painted Lady butterflies as well as other species are important pollinators for native plants.  Their long proboscis can be more effective at pollination for certain native wildflowers than bees for example.  Native plants are likewise essential for maintaining homeostasis with natural population balances, keeping fungi, bacteria and insects numbers relative to proper balances.

As Painted Lady larvae mature they may develop yellow and black stripes.  One important facet of organic based Integrated Pest Management is an understanding of where pests come from, or pest vector recognition.  Although native insect eradication is not a good idea, and actually a practice that may further aggravate invasive pest problems, it is important to understand where and under what conditions insects thrive.

Painted Lady butterfly host plants include thistles, wild asters and plants in the Boraginaceae and Malvaceae (okra, cotton and mallow) families. 

Large populations of thistle or aster plants may become breeding grounds that create out of balance, excessive population numbers of Painted Lady butterflies.  In natural systems fire among other events control host plant populations thereby keeping insect population numbers in balance.

Within today's agricultural systems many natural events, like fires and deep biodiversity, are suppressed.

Once the hemp grower recognizes host plants for their importance and limiting roles they serve then overall ecosystem and pest balancing is easier to achieve.

Bird feeders around thistle or sunflower patches are one potential approach.  Birds utilize caterpillars as food.  Several bird feeders set up just inside your fence adjacent to a roadside thistle patch can serve to keep Painted Lady butterfly and caterpillar populations from becoming destructive and overwhelming.

Painted Lady caterpillars and butterflies are just one type of many native yet potential destructive 'bugs'.

Learning to recognize the 'bug' and understanding their lifecycles and host plants are all necessary components of an organic IPM program designed to maximize hemp production.  Rather than approach organic IPM from the perspective of 'how do we keep nature out of our hemp populations', we must figure out how to effectively integrate hemp cultivation into a balanced ecosystem in which we live.

Hemp cultivation operations existing 'in-sync' with a balanced surrounding ecosystem will be highly productive and efficient.  Organic IPM programs can be one of the hemp farmer's best grow partners.