Aphids Affecting Cannabis

Aphids are true insects within the order Hemiptera. Aphids are a relatively small group of insects, yet they are of serious economic concern in a variety of crops. About 25% of known crop species are affected by aphids. About 100 species are of serious economic importance [2]. They have a worldwide distribution, but are most commonly found in temperate regions. They can travel large distances passively on strong winds.

Most adult aphids do not develop wings, but a some do [3]. They feed on plants by utilizing a needle-like organ called a stylet. This allows them to bypass the plant cuticle and cells that contain defensive compounds.

Aphids are phloem-feeding, piercing, sucking pests that present a threat to crops through at least 4 mechanisms:

  1. Feeding damage- diverts nutrients intended for plant growth and reproduction to the aphids, causes physical plant damage which can lead to lower photosynthetic rates, increased transpiration, and lesions that can lead to pathogen infections.
  2. The injection of phytotoxins in to the plant during aphid feeding which can damage plant health and growth.
  3. Aphids are the most common vector of plant viruses. Nearly 50% of plant viruses can be transmitted by aphids [2], including viruses confirmed in Cannabis such as Cucumber Mosaic Virus (CMV) and Alfalfa Mosaic Virus (AMV) [3].
  4. Honeydew left on foliage by aphids can support the growth of sooty mold on leaf surfaces, leading to negatively impacted photosynthetic rates.

Cannabis produces the terpene β– farnesene, which acts as an alarm pheromone in the aphids [3].

What Aphid Species Affect Cannabis?

At least six species have been reported to infest Cannabis plants [3]. However, more recent information has challenged previous claims about which species colonize Cannabis. In Colorado, M. persicae and P. humuli were unable to survive on hemp plants after manual inoculation. It may be that previous reports of M. persicae and P. humuli as pests of Cannabis were actually misidentification of the Cannabis aphid, P. cannabis. Aphis fabae has only been reported once in the literature, and it may be possible that these other species may be misidentified or uncommon pests [14]. Given this information, IPM choices should generally focus on controlling P. cannabis, not other aphid species.

Myzus persicae (Green peach aphid)

A green (sometimes yellowish or even pink) aphid that is fairly large (about 2.0-3.4 mm long). The nymphs of the winged adults (alatae forms) are usually pink or red, while the adults have black-brown heads and a black spot on their abdomen.

In general, aphids are heteroecious, meaning that they migrate between two different hosts. M. persicae overwinters on Prunus species such as cherry or peach trees as eggs laid on limbs or tree bud axils. When eggs hatch, they give birth to fundatrices (stem mothers). These fundatrices can reproduce parthenogenically (asexually); they give live birth to 60-100 wingless clonal larvae called fundatrigeniae. The fundatrigaeniae give birth to more wingless females asexually (apterae or apterous viviparae). This continues until spring, when the first winged (alatae) aphids develop. These alatae females fly to alternate hosts such as Cannabis and produce more apterae offspring. Each aptera gives birth to 30-70 offspring until food becomes restricted, at which point new alatae (summer migrants) are produced to find new Cannabis plants. To reach maturity, each aptera offpring goes through about four molts on Cannabis. At the end of the summer, the aphids return to the primary host by special alatae called sexuparae. Upon return to Prunus hosts, the sexuparae give birth to ten sexuales.

In controlled indoor or greenhouse environments, M. persicae can replicate all year long parthenogenically on Cannabis.

can be male/female or alatous/apterous. When sexuales mate, females lay 5-10 eggs which overwinter on Prunus species. Using this life cycle, they are able to asexually amplify their populations on primary and secondary hosts.

Female adult green peach aphids, Myzus persicae (Sulzer), with immatures.
Image From http://entnemdept.ufl.edu/creatures/veg/aphid/green_peach_aphid.htm

Black Bean AphidAphis fabae

Overwintering host- Euonymus or Virburnum species.They represent at least 4 subspecies, and which subspecies which attacks Cannabis is unknown. Like M. persicae, eggs hatch in to fundatrices, followed by fundatrigeniae, then apterae. The rest of the life cycle is similar to M. persicae, and in the spring, winged females may infest Cannabis plants, which then produce more aphids asexually. They are found in all temperate regions except Australia, they infect many crops, and may vector over 30 viruses.

Aphids May 2010-3.jpg
Image from https://en.wikipedia.org/wiki/Black_bean_aphid

Bhang Aphid/Hemp Louse- Phorodon cannabis

These aphids are about 25% smaller than M. persicae (1.9-2.7 mm long). Their color can vary from colorless to bright green with dark green stripes. Alatae (winged) larvae are smaller than apterae larvae and have dark patches on the head and abdomen. Unlike M. persicae, P. cannabis does not alternate hosts (autoecious), and so sexuparae lay eggs directly on Cannabis, particularly on flowering tops. It has evolved to complete its entire life cycle on Cannabis plants.

As previously mentioned, P. cannabis is most damaging to Cannabis flowers; it prefers to feed on flower sepals and in seeded Cannabis, and shelter in between seeds and sepals. The bhang aphid has been reported as a common vector of Cannabis viruses including the hemp streak virus, hemp mosaic virus, cucumber mosaic virus, alfalfa mosaic virus, hemp mottle virus, and hemp leaf chlorosis virus. P. cannabis may have evolved from P. humuli, because it is autoecious but is indistinguishable from P. humuli aside from the smaller head of P. humuli and fewer bristles.

Image from https://influentialpoints.com/Gallery/Phorodon_cannabis_hemp_aphid.htm
Image from https://influentialpoints.com/Gallery/Phorodon_cannabis_hemp_aphid.htm

P. humuli

Much like M. persicae, P. humuli is heteroecious and overwinters on Prunus species. In the CA bay and southern England, spring migration of P. humuli alatae females to Cannabis happens in early and late June, respectively. Females can travel up to 150 km by wind. P. humuli normally infests hops, but can also infest Cannabis [3].

Phorodon humuli
Image from https://bugguide.net/node/view/637027

Melon aphid (A. gossypii)

First noted on marijuana in India, they are fairly small at 1-2 mm long. Color may vary from light yellow to dark green. The species has a broad host range but prefers warmer temperatures around 27°C and is a common vector of plant viruses.

Nymphs (mixed ages) and dark form of wingless adult of melon aphids, Aphis gossypii Glover.
Image from http://entnemdept.ufl.edu/creatures/veg/aphid/melon_aphid.htm

Abstrusomyzus phloxae

An aphid with a fairly large host range that has been reported in California in 2018 [31]. There is little information on this aphid, but it appears to be primarily asexual, with females producing parthenogenetically [32]. I am unsure how aggressive of pests they are, but they have been reported from both indoor and outdoor grows.

Image from https://aphidtrek.org/?page_id=32

Light green aphids- Consider M. persicae, P. humuli, and P. cannabis, though M. persicae is the largest of these species.

Dark green to black aphids- Points towards A. fabae or A. gossypii.

Distinguishing features between aphid species are usually based on the insect size, color/length of tubercles and cornicles or the size/presence of a midline knob. For instance, P. humuli and P. cannabis are smaller than M. persicae.

Signs and Symptoms of Aphid Infestation

Like mites, aphids tend to concenctrate on the undersides of leaves. Some species prefer lower leaves, such as Myzus persicae, and some species tend to feed on upper leaves Aphis fabae [3]. Some species of aphids even feed on the buds themselves, such as Phorodon humuli and P. cannabis, though they also feed on leaves.

Early symptoms are hard to detect, because they tend to be light colored spots on the bottoms of leaves near veins. It is important to check all parts of the foliage when you scout. As infestations progess, you will begin to notice distortions and strange growth patterns on developing foliage or flowers. Very severe infestations can result in plant wilt and even death.

Image from https://www.leafly.com/news/science-tech/the-curious-case-of-the-cannabis-aphid

Honeydew is another symptom of aphid infestation. It can sometimes be seen as shiny spots on the leaves, but it tends to not be very apparent on Cannabis leaves.

Aphid producing honeydew

Symptoms such as wilting or yellowing can sometimes be confused with symptoms caused by mites or whitelfies. Aphids have long wings at least twice the span of their body length, winged insects such as fungus gnats have shorter wings.

Control

There is not a lot of information on control of the Cannabis aphid, as it is a fairly new pest in North America. Most recommendations will be based on control methods demonstrated to be effective on other aphid systems.

For indoor grows, sanitation and pest exclusion are very important. All air intake should be filtered or screened to exclude alatus (winged) females. Those entering the grow space should wash and not wear any clothing worn outside.

Genetic resistance introduced through selective breeding is a likely source of future control techniques, but right now there is not much knowledge as to which cultivars may be more resistant than others to aphid infestation.

Biological Control

Microbial Products

Bacillus thuringiensis-based products may have minor efficacy against some aphid species, but generally speaking is not a good choice for controlling aphids or piercing-sucking pests in general.

Monterey LG6332 Bacillus Thuringiensis (B.t.) Worm & Caterpillar Killer Insecticide/Pesticide Treatment Concentrate, 16 oz

Safer Brand 5163 Caterpillar Killer II Concentrate, 16 oz

Grandevo CG- Chromobacterium subtsugae

This product contains heat-killed bacteria as well as secreted metabolites. It works through various mechanisms of action

C. subtsugae is part of a recommended control program of the hop aphid (Phorodon humuli) along with B. bassiana and azadirachtin. Based on this, it has also been suggested as a control method for the very closely related Cannabis aphid (P. cannabis) [5].

Marrone Bio Innovations Grandevo WDG Bioinsecticide Miticide OMRI Listed – 6 lbs – 2019 Reformulated

Venerate CG- Burkholderia spp. strain A396

Like Grandevo, Venerate consists of heat-killed bacteria and secreted metabolites. Venerate is quite effective against M. persicae and is comparable with spirotetramat. It is more effective than C. subtsugae (i.e. Grandevo) for the green peach aphid [4]. For more broad control of various aphid species and other insect pests, it is recommended to rotate Venerate and Grandevo on a 7 day cycle.

Venerate CG Bioinsecticide Insecticide for Mites, Thrips, aphids, borers, whitefly, leafhoppers on Grapes, Strawberries, Potatoes, Citrus and More (1, Quart)

Marrone Bio Innovations Venerate CG Gallon

Beauveria bassiana

B. bassiana metabolites may have insecticidal activity towards aphids even without viable cells. B. bassiana culture filtrate (no living cells) is effective at controlling M. persicae [6], and even endophytic B. bassiana may negatively impact aphid populations on the colonized host plant [7]. B. bassiana has been shown to be effective against other aphids such as Macrosiphum rosae (the rose aphid), and Aphis gossypii (melon aphid) [8, 9]. It may also be effective against the cannabis aphid, as it has been demonstrated to be effective against the closely related hop aphid (Phorodon humuli) [10]. It is important that relative humidity is fairly high for B. bassiana to be effective. Ambient humidity levels should be at least 50% and the humidity at leaf surface would preferably be close to 80%.

BotaniGard 22WP Biological Insecticide 1lb

Isaria fumosorosea

Like B. bassiana, I. fumosorosea consists of live fungal spores and can spread throughout an insect population as the fungus sporulates on deceased insects. It has been demonstrated to be effective against some aphid species such as the brown citrus aphid [11], M. persicae [12]. It has limited effects on beneficial insects or predators and can be used along with other microbial insecticides. I. fumosorosea effectiveness may be decreased by the use of horticultural oils [13].

Purchase product PFR-97 from Certis USA, not available on Amazon.

Aphid Predators and Parasitoids

Green Lacewing (Chrysoperla carnea)

This larvae of this species are effective at keeping aphid populations low and preventing outbreaks without chemical control. Only the larvae are predatory. Adults lay eggs proximal to aphid colonies. They are also effective control for other common pests such as whiteflies. They tend to be most effective in enclosed locations with environmental control (indoor and greenhouses). They can tolerate warm temperatures, but do not operate well in cold environments. The ideal temperature and RH level is 20 ° C to 31 ° C and 70% respectively. Maintenance release rates are usually around 1,000-2,000 eggs/acre and infestation response can be up to 10,000 eggs/acre.

Green Lacewing Life Cycle
Image from https://biocontrol.entomology.cornell.edu/predators/Chrysoperla.php

Nature’s Good Guys Green Lacewing 1,000 Eggs – Slow Release Hanging Bag

Green Lacewing 5,000 Eggs – Organic Natural Aphid Control

Green Lacewing 10,000 Eggs – Organic Natural Aphid Control

Lady Bugs/Beeltes

I do not generally recommend ladybug releases for aphid control in Cannabis as a control method, unless in an enclosed environment with very high release rates. There needs to be a high population of aphids to keep them alive, and may require over 1,000 lady bugs per plant to actually get the issue under control. However, they can potentially work when released in high numbers in proper environments. For populations to persist, they may need to be misted. Most commercially available lady beetles are convergent lady beetles, as they are easily collected in large numbers from overwintering sites. It may take a couple weeks after release in optimal conditions for them to become fully active predators.

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Parasitoid Wasps

The parasitoids in the subfamily Aphidiinae are small wasps (0.08 – 0.12 inches). Some species are commercially available for aphid control. Adult wasps lay eggs inside of aphid hosts. The eggs hatch inside aphids and the larvae begin to feed on aphid tissue. In later development, the larvae kill the aphids and pupate inside the mummies. They exit the aphids as mature wasps.

Commercially available parasitoids are within the genera Aphidius (Hymenoptera: Braconidae) and Aphelinus (Hymenoptera: Braconidae). Like predators, parasitoids are most effective when aphid populations are low. However, in certain systems, it has been demonstrated that using both predators and parasitoids together is more effective than using one or the other [14. 15].

Aphidius colemani

These parasitoids are effectively used in glasshouses and outdoors in temperate regions. Ideal conditions are 70-77°F and relatively high humidty (~80%). Temperatures above 85°F halt parasitoid development, but in 50°F temperatures, parasitoids may still develop. Humidity is relatively less important, and development may still occur even in low humidity. If the humidity is sufficient for They are sold as aphid mummies from which wasps emerge or as newly emerged adults. They are useful in the winter because they are not affected by short days, but aphids are generally not a problem in cold weather anyways. They are commonly used for control of M. persicae, but have also been observed to parasitize the more feared and recently introduced cannabis aphid (Phorodon cannabis).

A. ervi

This is another parasitoid that has been found to complete its life cycle using P. cannabis as the host. Life cycle and environmental conditions are similar to A. colemani

Aphid Midge (Aphidoletes aphidimyza)

These midges are cecidomyiid flies that are effective aphid predators. Like green lacewings, it is the larvae that feed on the aphids. It is common to release aphid midges along with green lacewings to increase predator diversity, as each predator may fill different niches better. Adults are small (2-3mm) and resemble mosquitos, while larvae look like small orange maggots that can also reach 2-3mm in size. Eggs are laid in foliage, and the larvae begin feeding on aphids on the plants after hatching, then they drop to the soil within a week to pupate. Larvae can eat up to 80 aphids but require at least 7 to complete the life cycle [27]. These midges are less affected by azadirachtin than green lacewings. While green lacewings larvae are not killed by azadirachtin, it may interfere to some degree with the egg-laying of female lacewings. For this reason, it may be worth it to use midges either in place of or supplementary to release of lacewings if you are also using neem or azadirachtin [28]. They will go in to diapause if the day length drops below 12 hours or temperatures are below 50 farenheit. They require soil and will not work in hydroponic systems [29].

Minute Pirate Bugs (Orius insidiosus)

Beware! These insects have a painful bite. They are good generalist predators that do well with controlling thrips and aphids. They reproduce fairly quickly, completing their life cycle in under a month. They do well at temperatures between 64-82°F, with 60% RH. It is recommended to release 100-2000 per acre depending on pest population.

Most beneficial insects are not available on Amazon. Check out Arbico Organics at arbico-organics.com

Chemical Control

Azadirachtin and Neem Oil

Both neem oil and azadirachtin are effective in controlling various aphid species, but the efficacy of the compounds varies depending on the aphid species [17]. It appears that insecticidal activity is not due to antifeedant activity, but instead inhibits reproduction and molting. Neem appears relatively harmless to many beneficial insects and can usually be used along with other strategies. When utilizing fungal biocontrol such as B. bassiana or I. fumosorosea, azadirachtin may be more compatible than complex mixtures such as neem oil.

Organic Neem Bliss 100% Pure Cold Pressed Neem Seed Oil – (16 oz) High Azadirachtin Content – OMRI Listed for Organic Use

Organic Neem Bliss 100% Pure Cold Pressed Neem Seed Oil 32 oz – OMRI Listed for Organic Use

General Hydroponics GH2045 AzaMax, 4 Ounce

General Hydroponics AzaMax, 16 oz GH2007

Insecticidal Soaps

The active ingredients of these soaps are potassium salts of fatty acids. The soap is able to disrupt the cuticle of the insect, essentially leading to death through desiccation. They are contact pesticides that have no residual pesticidal activity. They are also very broad spectrum pesticides and will kill beneficial insects as well as pests. Because of this, it is not recommended to use insecticidal soaps concurrently with beneficial insect release. However, they can be used as a useful knock down spray to reduce initial populations. Water sprays can be effective at reducing the populations just by knocking aphids of the plants, but using insecticidal soaps ensures that aphids knocked off do not find their ways back to the plants. Soaps can also be mixed with other insecticides including pyrethrins, horticultural oil, essential oils, triglycerides, or azadirachtin and neem products. While good as a part of an IPM program, neem oil and azadirachtin are not as effective against P. humuli as pyrethins, insecticidal soaps, or beneficial fungi [18]. Based on anecdotal evidence, I believe neem is less effective on P. cannabis than on some other aphid species, but should still be used preventatively or tank mixed with other insecticides as a knock down treatment.

Safer Brand 5118-6 Insect Killing Soap Concentrate 16oz

Natria 706230A Insecticidal Soap Organic Miticide, 24 oz, Ready-to-Use

Safer Brand 5110-6 Insect Killing Soap, 32 oz.

Pyrethrins

Pyrethrins are insecticides found in some chrysanthemum. Due to the source, they can be used in organic production. Usually, formulations have six chemicals found in the flowers. They are non-persistent and typically degrade within a few days when exposed to the environment and sun. Synthetic pesticides called pyrethroids have been made that mimic the activity of pyrethrins, do not degrade readily, but are not approved for use in Cannabis. Pyrethrins are much lower risk than pyrethroids for both consumer health and meeting pesticide testing limits. However, there have been reports of flower failing residue limit tests of pyrethrins and it is not fully understood why. Piperonyl butoxide (PBO) can be mixed with pyrethrins as a synergist. PBO works by inhibiting insect enzymes that may help break down pyrethrins. Pyrethrins are quite effective as an initial knockdown.

PyGanic Gardening 8oz, Botanical Insecticide Pyrethrin Concentrate for Organic Gardening

Pyrethrins can be mixed with insecticidal soaps or neem products such as azadirachtin

Safer Pyrethrin & Insecticidal Soap Concentrate, 1 Gallon

Azera Gardening 8 oz, Botanical Dual Action Azadirachtin/Pyrethrin Fast-Acting Insecticidal Concentrate for Organic Gardening.

Horticultural Oils (Triglycerides, Mineral Oil, Essential Oils)

Most horticultural oils, particularly mineral oils and plant fat oils, work by suffocating insects and blocking respiration. Mineral oils are composed of higher alkanes derived from petroleum, and plant oils are mainly triglycerides. Triglycerides are composed of a glycerol molecule bound to three fatty acids which may be saturated or unsaturated. Most horticultural oils are most effective when mixed with a surfactant that helps spread the oils and may help deliver the oils more effectively to insect spiracles. Horticultural oils are also quite effective against fungi, particularly epidermal-limited pathogens such as powdery mildew.

Plant oils tend to be harsher on the plant epidermis than refined mineral oils and can more easily result in leaf burn. However, many plant oils contain other fat-soluble secondary metabolites that may have insecticidal activity. For instance, neem oil contains azadirachtin which inhibits insect reproduction and molting, but it also has triglycerides that work through suffocation. Other common plant oils used as insecticides include corn oil, soybean oil, canola oil, and other vegetable oils.

Various plant-derived essential oils can also have insecticidal activity. Essential oils can be derived in a variety of ways, most frequently by steam distillation followed by separation of the non aqueous layer or by solvent extraction. Steam distillation results in a high concentration of low molecular weight, nonpolar, volatile (easily becomes gaseous) chemicals including small terpenes, aldehydes, alcohols, and esters. Fatty acids are not easily recovered through distillation. Solvent extraction with nonpolar solvents such as hexane can also recover these chemicals, but during the solvent removal, many of the smaller volatiles may be lost and larger nonpolar molecules may remain. Essential oils also can be present in cold press extracts along with fatty acids.

One such essential oil product is Trifecta Crop Control. Along with essential oils, the product contains corn oil, citric acid, and an emulsifier. According to the Trifecta website, Trifecta works through more complex mechanisms than simply suffocation: clove oil contains eugenol: a terpene that causes cell lysis in fungal species, peppermint oil for reproductive inhibition, garlic oil for repellency and to treat systemic fungal infections, thyme oil for endocrine disruption in soft body pests, corn oil as a suffocant, and citric acid for chelating calcium in insect’s exoskeletons [19].

Trifecta Crop Control Super Concentrate All-in-One Natural Pesticide, Fungicide, Miticide, Insecticide, Eliminate Spider Mites, Powdery Mildew, Botrytis, Mold and More on Plants Non-Toxic 4oz

Monterey LG 6299 Horticultural Oil Concentrate Insecticide/Pesticide Treatment for Control of Insects, 32 oz

IPM Concepts

If you wish to avoid chemical control altogether, it is possible to achieve good levels of prevention using predator insects and parasitoids. It is generally recommended to use both parasitoids and insects within the generalist predator guild. For instance, weekly to biweekly release of green lacewings (5,000-10,000 eggs/acre) and parasitoid Aphidius species (500 aphid mummies/acre) can provide good control and release numbers can be increased up to tenfold at the first sign of infestation. Other insects that can be purchased and released are convergent lady beetles (Hippodamia convergens) and minute pirate bugs (Orius insidiosus).

Compared to many synthetic insecticides, neem and azadirachtin products tend to be relatively benign to beneficial insect populations [17]. Undoubtedly, neem has negative effects on the total predator population, but the number of surviving predators relative to the number of surviving aphids is not significantly different, and the aphid parasitism rate by Aphidius can actually increase [17]. However, it is important to mitigate the negative effects of neem on predators by using proper application timing. For instance, spraying neem 24 hours before predator release will allow for the knockdown effect of neem while preventing the predators from coming in to direct contact with the neem. If releasing predators on a biweekly basis, neem can also be sprayed at the same frequency but one day prior to release. If you alternate between release and neem on a weekly basis, or if you spray neem directly after predator release, you can negatively effect the predator populations [20].

In regards to entomopathogenic fungi, B. bassiana is fairly similar to neem in that it has little effect on beneficial insects if it is sprayed before release of beneficials. B. bassiana can colonize some host plant endophytically, and the predatory effects of green lacewings does not appear to be negatively affected by feeding on aphids that have been sprayed with B. bassiana spores or aphids that are feeding on plants that have been endophytically colonized by B. bassiana [21]. However, spraying green lacewings directly with B. bassiana spore suspensions can negatively affect lacewing populations [22]. B. bassiana may be incompatible with lady beetles as well. Therefore, it is a good idea to time applications to minimize off target effects. One study that looked at the timing of B. bassiana in relation to release of parasitoid A. colemani demonstrated that ideal B. bassiana spray timing is approximately 3 days after M. persicae parasitism by A. colemani. There is speculation that immature parasitoids may produce fungistatic or fungicidal metabolites to prevent the entomopathogenic fungi from killing the hosts. Furthermore, aphids colonized by B. bassiana prior to oviposition by parasitoids appear to reduce the success of parasitoids [22].

B. bassiana can infect minute soldier bugs quite well, as well as convergent lady beetles, but it can be feasibly used with lacewings and parasitoids by using a timing such as the following:

Infestation Response:

  1. At first sign of aphid infestation, do a knockdown spray with a product such as pyrethrins (recommended for Cannabis aphid), or pyrethrins mixed with insecticidal soap.
  2. When dry, release parasitoid Aphidius wasps (up to 4,000/acre depending on population). These are high release rates and in most cases, fewer should be sufficient.
  3. 4-5 days after wasp release (if using adults), spray with B. bassiana product such as Botanigard
  4. After dry, release green lacewings up to 10,000 per acre, aphid midges, and up to 5,000 minute pirate bugs/acre, depending on populations. This is only in severe infestations, even half of these numbers should be sufficient for more infestations.

Maintenance/Prevention

  1. Do weekly release of predators and parasitoids at lower levels of 400 wasps, 200 minute pirate bugs, 1,000 lacewings, and 1,000 aphid midges per acre to suppress levels. This is a mixture of 4 good beneficials, but you can cut back to parasitoid wasps and one or two of the predators rather than using all of them.
  2. Use a rotation of Grandevo, Venerate, and Neem Oil. A rotation of any 2 products in this list could also be used. Both Grandevo and Venerate do not affect beneficial insects, and neem oil has low toxicity that can be mitigated with proper application timing.

If you do not want to use pyrethrins as a knockdown, I would recommend using a product such as Trifecta that contians an insecticidal soap, citric acid, essential oils, and corn oil. Please do not use Spinosad or synthetic pesticides in commercial operations as they are not labeled for use in Cannabis and are tested for.

Isaria fumosorosea may be even more effective than B. bassiana, at least in the case of M. persicae [24], and is of similar effectiveness as B. bassiana on the hop aphid (Phorodon humuli), closely related to P. cannabis [26]. For all applications of B. bassiana, it may be worth either trying I. fumosorosea or rotating between application of B. bassiana and I. fumosorosea. For both of these fungi, high humidity is ideal and ambiet humidity should not be below 50%, with higher humidities being more effective.

  1. Dedryver, C.-A., Le Ralec, A., & Fabre, F. (2010). The conflicting relationships between aphids and men: A review of aphid damage and control strategies. Comptes Rendus Biologies, 333(6), 539–553. https://doi.org/https://doi.org/10.1016/j.crvi.2010.03.009
  2. APHIDS: What You Want to Know About Them and How to Organically Get Rid of an Aphid Infestation in Your Cannabis — Ed Rosenthal. (n.d.). Retrieved April 21, 2020, from https://www.edrosenthal.com/the-guru-of-ganja-blog/aphids-what-you-want-to-know-about-them-and-how-to-organically-get-rid-of-an-aphid-infestation-in-your-cannabis
  3. McPartland, J. M., Clarke, R. C., & Watson, D. P. (2000). Hemp
  4. diseases and pests: management and biological control: an advanced treatise. CABI.
  5. Shannag, H. K., & Capinera, J. L. (2018). Comparative Effects of Two Novel Betaproteobacteriabased Insecticides on Myzus persicae (Hemiptera: Aphididae) and Phenacoccus madeirensis (Hemiptera: Pseudococcidae). Florida Entomologist, 101(2), 212–218. https://doi.org/10.1653/024.101.0209
  6. OREGON DEPARTMENT OF AGRICULTURE FACT SHEETS AND PEST ALERTS. (n.d.). Retrieved April 26, 2020, from http://www.Oregon.gov/ODA
  7. Kim, J. J., Jeong, G., Han, J. H., & Lee, S. (2013). Biological Control of Aphid Using Fungal Culture and Culture Filtrates of Beauveria bassiana. Mycobiology, 41(4), 221–224. https://doi.org/10.5941/MYCO.2013.41.4.221
  8. Endophytic Beauveria bassiana negatively impacts green peach aphids on strawberries – E-Journal of Entomology and Biologicals – ANR Blogs. (n.d.). Retrieved April 26, 2020, from https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=21711
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