Organic Florida Hemp Cultivation, Identifying Crop Pests with UV Light

Evolution has equipped many insects with a sublime ability to camouflage themselves. 

Pest Insects may remain hidden under most light wavelengths as shown here on a greenhouse lemon balm plant.

Insects may stay hidden under daylight wavelengths too.

Evolution has equipped many insects with effective camouflage appearances

Interestingly and importantly for the grower, ultraviolet lights used at night that produce illumination in the wave range between 300nm and 400 nm can often illuminate otherwise camouflaged pest insects.

UVb light can assist in identifying the presence of crop pests

Pest reconnaissance of crops in cultivation areas including those in row plantings and in the greenhouses can be conducted at night often with successful results for insect identification efforts.

Insects, plant damage, and even chlorophyll containing algae and cyanobacteria can be identified at night by examining plant stems, leaves and flowers using UVa and UVb lights. Many insects react to UV light through florescence of phosphors in their exoskeletons. Chlorophyll on the other hand under UVb absorbs all light waves except for 'red' wavelengths which are reflected back.  Algae growing across cultivation areas can easily be identified using UVb light.

Not all insects that glow under UV light are considered pests.  Potentially beneficial organisms such as stick insects, millipedes and even anoles can be easily spotted using UVa and UVb flashlights.

My personal favorite light for night insect surveillance are lithium rechargable, well built LED units with UVb filters.

Though the grower may not spot all pest insects on their greenhouse or row crop plants, chances are any key pest infestation can be quickly identified.

Florida Hemp Cultivation Bed Preparation

 Hay arrived yesterday for spring gardens.

Hemp cultivation is made easier with a quality mulch such as organic hay.

Excellent quality organic hay is useful as a mulch in the hemp garden, usually a bit more pest free than our mulched leaves.

We do mulch and reuse our leaves too however we find hay to be a favorite for maintaining soil moisture, keeping soils less compacted and not as hot, for buffering pH and contributing to overall organic matter content.

Hay is easily to spread, lightweight and readily & sustainably available on a local basis.

Planting Bed Prep for Spring Organic Hemp Crop

We began breaking soil and adding mulched organic matter from the Arendell Hill site in preparation for spring hemp planting.

In addition to the mulched organic leaf litter bird feeder platforms are now added to the cultivation area. Arendell Hill is a favorite foraging location for all types of birds, from large raptors to small songbirds. 

We enlist the birds to protect our hemp plants. Songbirds work efficiently in eating certain pest insects such as caterpillars, beetles and bugs. 

Planted around the base of the bird feeders are native plants and wildflowers such as spotted bee balm, Monarda punctate. M. punctate attracts predatory wasps and other beneficial insects such as the assassin bug. Predatory wasps and assassin bugs control many cannabis crop pests through a variety of methods.

Arendell Hill Nursery employs a complex and highly integrated matrix of natural and organic pest control approaches. An understanding how the cultivation site's ecosystematics function allows the grower to take advantage of each and every biological, meteorological and geological variable for growing amazing quality CBD and CBG rich flowers. 

Leaf Footed Bugs, Friend or Foe to Organic Hemp Cultivation?

Leaf footed bugs, Leptoglossus spp., are larger size, primarily vegetarian insects, that feed on seeds, vegetables, plant matter and fruit with their cutting and sucking proboscis-like mouth.

Adult leaf footed bug, Leptoglossus spp. on a pine

Named for their leaf-like feet appendages, Leaf footed bugs are polyphagous and will feed on hemp plants, tomatoes, fruit, squashes and other garden crops when available.  During months when crops are not readily available they will feed on plants and seeds, seeking out 'weedy' areas across the hemp cultivation site. These insects may be often seen on hemp and cannabis plant stems, buds and leaves.

Leaf footed bugs can damage hemp and vegetable crops

Adult leaf footed bugs can fly long distances.  I usually see them hiding, over-wintering, in wood piles during cooler months.  They lay their eggs during spring and summer and may produce several generations in a year.

Birds, spiders and predatory wasps, possibly the sand wasp, are all natural enemies of leaf footed bugs and help keep their population numbers managed.

Though not the worst pest insect to the organic hemp or vegetable grower, they can inflict damage to both plant and flower.  In a well balanced horticultural ecosystem they can provide forage to other insects and wildlife and as such provide a certain level of food chain importance.

Certain species of thistles seem to attract leaf footed bugs as well as citrus.  Thistles are also quite beneficial in their supporting relationship to useful pollinators, birds and other natural pest predators. Native plant species such as milkweeds and mints are an important tool as they attract leaf footed bug enemies, such as predatory wasps.

A organic based integrated pest management approach to managing leaf footed bugs on the hemp farm should include;

• native plants that attract predatory wasps
• plenty of bird feeding opportunities
• removal of unnecessary wood and debris piles
• spider habitat
• sighting notations in daily grow journal.

As long as the leaf footed bug population numbers are not out of control, their occasional presence should not be a priority concern to the hemp grower.  They can be however, a dynamic variable in the hemp garden's ecosystematic matrix and as such their presence should be recognized by the grower in the daily journal.

 

Rooting Bee Balm Cuttings Organically, Hemp Cultivation and Pest Control With Wasps

 Monarda punctata, spotted bee balm, is a native wildflower here in Florida and an important pest control plant at Arendell Hill.  Spotted bee balm attracts beneficial pollinators and wasps and beetles, such as native ladybugs. Spotted bee balm also serves as a decoy, diverting pest bugs away from hemp crops.  Seeking out Monarda's nectar, potential pest insects soon find themselves consumed by lady beetles, dragonflies and other insects foraging in the bee balm.

Organic Hemp IPM Incorporates Spotted Bee Balm, Arendell Hill Nursery

December, with its cooler and shorter days here in Florida is the perfect time to root cuttings.  I cut six to eight inch healthy stem tips from a thriving bee balm plant and place the cuttings in a 72 count seed tray filled with a mixture of perlite, vermiculite and rockwool.  Cuttings are placed in a shade house and misted every twenty minutes for ten seconds.

Organic Pest Control Plants; Monarda cuttings root easily without hormones

That is it.  In two to three weeks the cuttings are rooted and ready to be potted up into four inch pots filled with an organic potting mixture.

Moreover, a very important benefit of incorporating Monarda punctata into a native plant based organic pest control management plan for the hemp garden is the plant's ability to attract the predatory sand wasps!  Sand wasps are highly effective at controlling hemp damaging marmorated stink bugs.

A stink bug infestation can quickly devour much of a hemp crop in short time.

Fortunately sand wasps love to feed their larvae stink bugs.  Sand wasps are a group of predatory wasps that include the Astata and the brightly colored Bicyrtes species.  Sand wasps seek out the nectar of Monarda, mountain mint (Pycnanthemum spp.) and milkweeds (Asclepias spp).  Adult sand wasps especially love to hone in on the odor of marmorated stink bugs.

Mamorated stink bugs, Halyomorpha halys, are an exotic pest native to the far east but now widespread in North America.  These pests can inflict significant damage on hemp crops as well as cannabis and other agricultural plants.  Yet sand wasps will kill these stink bugs and carry their bodies into tunnels in the ground to feed wasp larvae where they live during maturation.

A single sand wasp may kill dozens of stink bugs across the hemp cultivation area, greatly reducing  potential pest damage risk.

Organic Hemp Pest Control involves many native plants, like Spotted Bee Balm which attracts beneficial insects

Spotted bee balm is also one of the most carefree and easiest native plants and wildflowers to grow, requiring little if any attention while being resilient to salt, wind and drought.

Native plants are often ignored when integrated pest management programs are developed for organic hemp cultivation, yet native plants offer so many benefits to the hemp and cannabis grower.  Just as Monarda punctata attracts the stink bug killing sand wasp, other native species too play host to insects, amphibians, reptiles and birds that work together as an efficient team, keeping ecosystem balanced and effectively reducing pest pressures on crops.

Organic Hemp Cultivation and Pest Control, Documenting Weather Patterns

 Some of the most important variables the organic hemp farmer can record and analyze are weather patterns impacting the growing area.

Weather patterns are often predictive of pest outbreaks.  Droughts, floods, excess heat or cold, humidity levels, solar radiation, geomagnetism and barometric pressure fluctuations can trigger pest population explosions and also initiate certain pest activities.

Temperature changes, such as prolonged heat waves may cause insects to become much more active.  Insects are cold-blooded (poikilotherms) organisms, meaning their body temperatures fluctuate with outside temperature variations and heat is not generated internally through biological processes.  Prolonged heat waves can fuel insect activity due to increased body temperatures.

Some have estimated that for each two degrees Fahrenheit rise in temperatures over normal ranges, pest insects may inflict ten to twenty percent more damage as their metabolism and body temperatures increase.  These observations suggest climate change could have serious impacts on hemp organic integrated pest management as well as for other agriculture product pest management systems.

Droughts too may trigger prolonged insect feeding activities as bugs search for water sources within plant buds, stems and leaves.  During droughts, hemp and cannabis pest insects may be driven to eat plant matter in search of moisture.  Regular precipitation measurements may provide the hemp farmer with patterns that help predict pest activity.

Organic Hemp Pest Control, Ambient Weather wifi enabled rain gauge

Climate and weather patterns can also be helpful in determining which beneficial insects, or pest predators are most productive in an organic pest control role under certain climate conditions.  Abnormal weather patterns such as drought, extreme temperatures, winds and humidity levels may actually work against beneficial insects and favor hemp pests.

There are many low cost, reliable weather stations available today that monitor, record and summarize growing area weather variables.  Ambient Weather, La Crosse Technology and Davis Instruments are a few of more popular retail available weather instruments.

Organic Hemp Cultivation, IPM methods, Ambient Weather Station

I use an Ambient Weather ultrasonic unit that measures temperature, relative humidity, wind speed, barometric pressure, sunrise and sunset hours and other important ecosystem geophysical variables.  The Ambient Weather station was inexpensive, easy to set up and summarizes weather trends over time.

Most of the small personal weather stations also provide the capabilities to connect to the internet, allowing for participation in crowd sourced weather data sites.

Weather and climate data are an important but small part of a hemp cultivation site's ecosystem variable population.   

Our agrarian ancestors understood the importance of understanding weather patterns.  Their food growing efforts depended on weather systems knowledge.  They watched and listened to the clouds, birds, animals and other tell-tale signs of impending climatic events.

Organic Hemp Pest Control, Ambient Weather data display

Today, the hemp farmer must also be able to comprehend meteorological impacts on crops.  A daily log of cultivation site weather data provides so much important information.

A thorough understanding of geophysical weather variables driving much of the hemp farm's growing parameters will support successful organic cultivation efforts.

The successful hemp cultivator will use all available organic-based integrated pest management tools.  Weather recording systems are a critical part of any organic IPM program on hemp farms.

Organic Hemp Cultivation, Integrated Pest Management (IPM) & Birds

 We encourage birds to make themselves home here in the Arendell Hill nursery gardens.

Wild birds, song birds, raptors and more.  Winged creatures serve an important part of our Organic IPM

I consider birds to be better than 'human help' at picking caterpillars and other potential pest insects out of our gardens.  Songbirds can keep the ground and shrubbery around a hemp cultivation area significantly free of larvae that are crawling around looking for leaves or flower buds to chew on.  Larger birds also, like red shouldered hawks here are vigilant in keeping the nursery free of disease vectoring rodent populations. 

Winged creatures have a definite advantage over crawling pests.  Winged predators can conduct reconnaissance across a ground area much quicker than most crawly pests can escape.  It is true that many insects can fly and are beneficial in their own ways, such as for pollination.  The advantage however lies with birds though due to their size, advanced development of senses and ability to quickly forage across large areas of garden.

Maintaining quality bird habitat for hemp farms should include practices that ensure ample bird forage provisions exist.  Feeders are one obvious way to attract birds and work well in creating a basic Integrated Pest Management program.  Yet bird feeders are just a start.  Native landscape plants that flower, fruit and produce seed are another worthwhile addition to bird feeders in hemp cultivation areas.

Importantly, once the grower begins to attract birds to their hemp growing area and the birds begin their caterpillar and pest insect control duty, the grower must also ensure that the farm provides a place for the birds to 'stay' and nest.  Communal habitat is best established by planting native landscape and wildlife value shrubs.  

American holly, Ilex opaca, provides forage and evergreen communal habitat to wild songbirds and as such can be an important part of an Organic Hemp IPM program. 

Native shrubs, rather than horticultural imported shrubs, will always be a wild songbird's and raptor's preference, for the native shrub's habit and familiarity are transcribed by countless previous generations into a bird's DNA.  Simply put, the wild songbirds are attracted to those native shrubs they and their ancestors have always lived in and around.   

It is true that some non-native horticultural shrubs and plants will also be utilized by wild birds.   However the net benefit to the hemp farm efficiency matrix will be reduced when using non-native landscape species.  In fact, it is possible non-native landscape plants can cause significant ecological systems damage.  When the growing ecosystem matrix becomes unbalanced pest pressure will increase.

As we will see in other posts, not only do native plant species support all important bird populations across the hemp farm, but native plant species also provide a number of other important pest control and nursery management functions.

We will also discuss in future posts, how to visualize the hemp farm bio-geophysical ecosystem matrix.  Though the name 'bio-geophysical ecosystem matrix' may sound complex, the concept is a simple one.  Everything affecting the hemp farm makes up the matrix.  There are many variables, such as birds, wildlife, rain, wind, temperatures, pests, soil, water and others.  The way these variables act upon and influence hemp plant growth in the garden is what the matrix is all about.

Another term I like to use when thinking about the ecosystem matrix is the phrase 'Languages of Nature'.  Each variable asserts an influence, good or bad, on the hemp plants.  Each good or bad influence can be known through interaction with our senses.  Ecosystems communicate the effects of most impacts they experience through measurable responses. An expert hemp farmer 'reads' and understands these ecosystem responses and utilizes the information to maximize crop efficiencies.

Importantly, songbirds and raptors are not the only winged creatures employed by organic hemp and plant nursery growers as part of an organic IPM program.  Chickens, bats and other critters have been successfully integrated into hemp farm pest control programs.  We will discuss these too in future posts.

Finally, it must be understood that birds can be vectors of plant diseases.  However when weighing the risks of potential bird vectored plant diseases versus the insect control benefit, the pest control benefit is usually greater than the disease risk.  

IPM risk benefit analysis can be established through trial and error on the farm, through research of peer reviewed literature and also through coordination with experts working with a local agricultural extension service.

Birds are just one part of a hemp farm ecosystem matrix complex, yet they are a beneficial part.  

Now it is time for me to go add bird food to the feeders!

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Eastern Tent Caterpillars (Malacosoma spp.) and Other Caterpillars in Hemp Cultivation

 Quality, organically grown hemp can bring a high level of demand and offer significant economic gain to the organic grower.  But tent caterpillars can devastate any crop, especially plump, fresh leaves and buds in a matter of hours when they are in a feeding frenzy.  In the eastern U.S. there are several species of tent caterpillars including the Forest Tent Caterpillar, Malacosoma disstria and the Eastern Tent Caterpillar, Malacosoma americanum.  

Eastern Tent Caterpillars crawling across the pavement in search of host plant material

The forest tent caterpillar typically weaves silken mats on tree trunks where they congregate after feeding and for protection.  Similarly, silky tents observed in the branches of trees are usually constructed by the eastern tent caterpillar.

Does Malacosoma americanum pose a serious threat to hemp?  Hemp may not be the first host plant of choice for the eastern tent caterpillar but there are reports in literature (Alexander 1984b) of M. americanum exerting negative pest influence on hemp.  It is possible that once a hungry population of tent caterpillars encounters hemp in cultivation, the caterpillars devour much of a crop without a second thought.  Moreover, in addition to the defoliation, many caterpillars leave copious amounts of feces in hemp's flower buds.

Regardless, this past year brought significant numbers of tent caterpillars to Arendell Hill's trees.  Several of our mature fruit trees were attacked by the caterpillars.  Unfortunately, they ate the majority of buds, blossoms and leaves from many of our citrus and fruit trees. 

 

It is easy to see just how many tent caterpillars are in a population once they are in their 'tent'.   During their developmental phases, tent caterpillars will crawl out of their nest and feed on the host plant leaves.

Caterpillar eggs can survive the winter attached to leaf litter and fallen tent masses

Worth repeating because of the tremendous potential economic damage a hemp cultivator can suffer is the fact that in addition to tent caterpillars damaging hemp plants by eating their foliage, caterpillars can leave copious amounts of feces as they crawl across and into, eating hemp flower buds.  A feces filled flower bud will usually be considered a total loss.

Eastern Tent Caterpillar's woven 'tent'.

The hemp farmer can avoid significant tent caterpillar damage by taking a few common sense pest management steps including; good housekeeping and a focus on cleanliness, support of biodiversity,  understanding host plant potential and actual pest identification.

First it is important to be able to correctly identify any potential hemp pest caterpillar.  Here in Florida the University of Florida's (UF) agricultural extension program can offer important help to farmers when it comes to growing almost any crop, including hemp.

Most counties in the state have an agricultural agent assigned and if the agent does not personally have the particular pest control experience one needs they will have access to the experts who do.

Here is the link to 'Find Your Local Agricultural Extension Office' website.

Your local agricultural extension agent will be able to assist you in identifying which of the species of tent caterpillars your growing operation may be challenged with.  In addition to the tent caterpillar issue, your UF extension agent can help with most any other crop pest issues. 

Along with the agricultural extension services discussed above, the internet is another resource to assist with in pest caterpillar identification.  One hack I always turn to includes snapping a photo with my phone camera and in turn doing a Google image search.  Although not as accurate by any means as the extension expert's identification help, the Google image search usually narrows down pest species choices to family or genus.  Many times however, I've been able to successfully identify caterpillar types through the Google image search function.

Once the caterpillar has been identified, in this case we've identified some of our caterpillars as the Eastern Tent Moth Caterpillar rather than the Forest Tent Caterpillar, then the grower must decide what level of attention needs to be aimed at the potential pest caterpillar.

If the ecological, environmental and economic damage potential is great then the hemp farmer may want to consider an eradication or extra strong management approach.  Eradication often involves pesticide applications, that though they may be considered 'organic' still possess moderate toxicity and lower the value and quality of the final hemp crop.  Additionally, organic pesticides ultimately make a pest problem worse by unbalancing of the farm's long-term, functioning ecosystem dynamics.

If the ecological, environmental and economic damage potential is more moderate but certainly in need of addressing then a focused management approach may be advised.  Moderately focused approaches can be taken many times when pest caterpillars first begin to appear and can include; traps, hand removal, facility cleaning, personal protective equipment, soil and container sterilization and more.

Caterpillar eggs may be attached to fallen leaves and hatch the next warm season.

Finally, if the potential pest is a slow reproducing and easy to control organism them monitoring may be all that is necessary.  Always keep good notes, including dates, times, events, pest numbers and types and control measures taken. 

One of the most common vectors of caterpillar and larvae are fallen leaves

Once the caterpillar has been identified and the level of necessity for adequate response has been decided them control actions can be implemented.

Most importantly, it is crucial to understand the best ecological, environmental and economic outcome will be achieved only when the hemp farmer can bring the growing operation into balance with the surrounding ecosystem that itself is functioning within normal ecological variables.  What this means from a pest control perspective is that any hemp operation will be mostly affected by pests which are themselves existing in an unbalanced state in the soil, vegetation and air in and around the hemp farm.

An eradication effort on the hemp growing area will be effective only as residual pesticide exists.  As soon as the pesticide is degraded additional pests will enter the growing area from the surrounding ecosystem where they are out of balance with respect to excess population numbers.  As the caterpillars continue to overwhelm more pesticides must be applied.  Eradication and pesticide measures use can easily turn into an unnecessary and damaging repetitive cycle.

In the end, many times eradication efforts do more crop damage than the original pest issue the grower sought to control.

However, once the surrounding ecosystem is balanced with respects to ecological dynamics then hemp crop pest control becomes much more manageable.

The hemp farmer must also consider and strive for ecological balance within the totality of their plot, not just their greenhouse or outdoor hemp garden.

As a hemp farmer I can keep tent caterpillars out of my green house on a consistent basis only if the surrounding land is balanced with normal tent caterpillar population dynamics.  If the tent caterpillar populations surrounding the hemp greenhouse are out of balance then eradicating them from the green house will only have momentary benefit.  They will crawl right back in once the pesticide level is no longer a deterrent. 

Supporting a natural ecological balance in and around the greenhouse or growing plot the farmer should manage the growing areas in a native and natural manner.  Area native ecosystems have evolved over the millennia into a harmonious complex system of interacting life forms.

Usually nature has fine tuned native ecosystems to function in a precise balance, one where all forms of life play a part and one where all natural geophysical and climatic conditions help maintain homeostasis.

Once humans become involved though we have a tendency to change an ecosystem's natural variables to suite our plans.  Examples of these impacts include; lack of fire, artificial irrigation, replacement of native plant flora with pest prone landscape plants, alteration of natural hydrology, alteration of native soils, change of noise levels, urban heat island effect and much more.

With respect to our tent caterpillars, annual wildfires suppressed for the safety of lives and property, allow a much greater quantity of tent caterpillar eggs to survive in the ground, on bark and on fallen leaves.

Historically, fallen leaves were usually part of the fuel annual lightening fires burned with and much of the egg bank was burned away.  However with a lack of fire today potential pest eggs can exponentially accumulate, creating population numbers that are much higher than in fire acclimated ecosystems.

In the hemp greenhouse and across the hemp cultivation area it is important to keep leaf litter cleaned up.  Leaves left to lie over the winter, especially those in piles under shrubs or around the base of fences make good incubation areas for next years caterpillars.

In the absence of fire, mowing and raking can help control pest eggs.

Leaf litter control is just one of the many integrated pest management control approaches a hemp grower can take.

I try and visualize my growing area as it would have functioned from a biophysical perspective as it might have before humans arrived.

Of the three pest management approaches mentioned above, an IPM approach to hemp cultivation, based on ecosystem principles consistent with balanced, native communities works best for growing quality, organic hemp products. 

We will look at the value of using native plants and avoiding horticultural landscape plantings around the hemp farm, as well wildlife and other IPM tools in upcoming posts.