MrSinilindin
- 13
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Has anyone been seeing what they suspect to be the Hemp Borer of old? I was surprised that the latin name did not come up here on the forums.
I've been seeing low yields, light webbing for quite some time (several small indoor harvests).
I've had mites, and spent a while thinking they had caused all the damage I was seeing.
But then I was inspecting some seeds I produced that weren't germing, and sure enough the seeds were damaged (the end, where it had been attached to the plant, is swollen like puckered lips, and there is a tiny hole on magnification).
So - after a massive disinfection, 24 hours sealed and dark, I open the door and this tiny moth flies right in my face.
I've seen the moth itself once or twice in several months, but they are quick, zig-zag fliers, and I can't seem to catch without smashing. They either hide well or don't spend much time as adults.
Likewise, the larvae are also tiny, and I have only seen them with 30X mag. At stem nodes.
So far the moth is not interested in UV zapper trap. I will continue to try to capture and post a pic.
But - the general question is - is this Hemp Borer circulating in CA or other legal climates? Anyone else seeing a moth that fits this description?
From McPartland, Cannabis Pests (1997)
I've been seeing low yields, light webbing for quite some time (several small indoor harvests).
I've had mites, and spent a while thinking they had caused all the damage I was seeing.
But then I was inspecting some seeds I produced that weren't germing, and sure enough the seeds were damaged (the end, where it had been attached to the plant, is swollen like puckered lips, and there is a tiny hole on magnification).
So - after a massive disinfection, 24 hours sealed and dark, I open the door and this tiny moth flies right in my face.
I've seen the moth itself once or twice in several months, but they are quick, zig-zag fliers, and I can't seem to catch without smashing. They either hide well or don't spend much time as adults.
Likewise, the larvae are also tiny, and I have only seen them with 30X mag. At stem nodes.
So far the moth is not interested in UV zapper trap. I will continue to try to capture and post a pic.
But - the general question is - is this Hemp Borer circulating in CA or other legal climates? Anyone else seeing a moth that fits this description?
From McPartland, Cannabis Pests (1997)
Probably the worst pests are stem-boring caterpillars, especially in fiber crops. Two economically important pests are the European corn borer (Ostrinia nubilalis), and the hemp borer (Grapholita delineana).
European corn borers (ECBs) attract a lot of scientific attention thanks to their amazing appetite for corn plants. ECBs are native to eastern Europe, where Cannabis sativa and Humulus lupulus (hops) served as original host plants. ECBs switched to maize after Zea mays cultivation began in Europe two centuries ago (Nagy 1976, 1986). About one century ago ECBs moved to North America and plagued American hemp, where they "nourished themselves upon the marrow within stalks" (Dodge 1898). More recently ECBs have infested marijuana crops (Bush Doctor 1987).
ECB feeding induces stem cankers, which are structurally weak. Stems supporting heavily flowering tops often break at cankers. Larvae boring into smaller branches cause wilting of distal plant parts. Under heavy infestations entire plants collapse. Emchuk (1937) states 5-12 larvae can destroy a hemp plant. ECB entry holes in stems are essentially open wounds, providing access for fungi such as Macrophomina phaseolina. Other insects may also crawl in. ECBs hatching late in the season may infest flowering tops instead of stems, where they spin webs and scatter feces.
Figure 1. Larva, pupa and female moth of Grapholita delineana (A) compared to larger Ostrinia nubilalis (B). Both about 1.5x actual size. (G. delineana from Senchenko and Timonina 1978, O. nubilalis from Ceapoiu 1958.)
Hemp borers (HBs) are smaller than ECBs (Figure 1). HBs cause similar stem damage and are much more destructive in flowering tops. HBs are also called hemp leaf rollers and hemp seed eaters. In Russia, HBs have destroyed 80% of a crop's flowering tops (Kryachko et al. 1965). Bes (1974) reports 41% seed losses in unprotected Yugoslavian hemp. Each larva consumes an average of 16 Cannabis seeds (Smith and Haney 1973). HBs appear host-specific on Cannabis (Mushtaque et al. 1973), so they have attracted attention as potential biocontrol agents against marijuana. Baloch et al. (1974) determined that 40 larvae will kill a Cannabis seedling (15-25 cm tall) in 10 days. As little as 10 larvae per plant cripple growth and seed production.
European corn borers (ECBs) attract a lot of scientific attention thanks to their amazing appetite for corn plants. ECBs are native to eastern Europe, where Cannabis sativa and Humulus lupulus (hops) served as original host plants. ECBs switched to maize after Zea mays cultivation began in Europe two centuries ago (Nagy 1976, 1986). About one century ago ECBs moved to North America and plagued American hemp, where they "nourished themselves upon the marrow within stalks" (Dodge 1898). More recently ECBs have infested marijuana crops (Bush Doctor 1987).
ECB feeding induces stem cankers, which are structurally weak. Stems supporting heavily flowering tops often break at cankers. Larvae boring into smaller branches cause wilting of distal plant parts. Under heavy infestations entire plants collapse. Emchuk (1937) states 5-12 larvae can destroy a hemp plant. ECB entry holes in stems are essentially open wounds, providing access for fungi such as Macrophomina phaseolina. Other insects may also crawl in. ECBs hatching late in the season may infest flowering tops instead of stems, where they spin webs and scatter feces.
Figure 1. Larva, pupa and female moth of Grapholita delineana (A) compared to larger Ostrinia nubilalis (B). Both about 1.5x actual size. (G. delineana from Senchenko and Timonina 1978, O. nubilalis from Ceapoiu 1958.)
Hemp borers (HBs) are smaller than ECBs (Figure 1). HBs cause similar stem damage and are much more destructive in flowering tops. HBs are also called hemp leaf rollers and hemp seed eaters. In Russia, HBs have destroyed 80% of a crop's flowering tops (Kryachko et al. 1965). Bes (1974) reports 41% seed losses in unprotected Yugoslavian hemp. Each larva consumes an average of 16 Cannabis seeds (Smith and Haney 1973). HBs appear host-specific on Cannabis (Mushtaque et al. 1973), so they have attracted attention as potential biocontrol agents against marijuana. Baloch et al. (1974) determined that 40 larvae will kill a Cannabis seedling (15-25 cm tall) in 10 days. As little as 10 larvae per plant cripple growth and seed production.
