Potential for Nezara viridula (Hemiptera: Pentatomidae) to Transmit Bacterial and Fungal Pathogens into Cotton Bolls

Abstract

Recently, we showed that the southern green stink bug (SGSB), Nezara viridula (L.), can transmit Pantoea agglomerans (Ewing and Fife), an opportunistic bacterium, into green cotton bolls resulting in plant disease. Here, we hypothesized that our established model could be used to determine if the SGSB was a general, non-discriminate vector by using two other opportunistic bacterial pathogens of bolls (Pantoea ananatis [Serano] and Klebsiella pneumoniae [Schroeter]) and the known fungal pathogen Nematospora coryli (Peglion). Variants of P. ananatis (strain Pa-1R) and K. pneumoniae (strain Kp 5-1R) selected for rifampicin (Rif) resistance were used as bacterial opportunists. N. coryli was detected only from laboratory-reared SGSB directly exposed to the fungus. Both Pa-1R and Kp 5-1R were recovered from SGSB previously provided a contaminated food source (2 days), sterile food (5 days), and then harvested after being caged on bolls (2 days) at levels reaching 10(3) and 10(4) colony forming units (cfus) per insect, respectively. However, bolls caged with insects infected with Pa-1R or Kp 5-1R and with evidence of feeding did not become diseased nor were either opportunists detected from boll tissues. Insects infected with N. coryli transmitted the pathogen, which resulted in diseased bolls and fungi concentrations reached 10(6) cfus/g locule tissue at 2 weeks following the caging period. Notably, each of the three pathogens independently caused boll disease when mechanically inoculated using a needle puncture. Generally, these results suggest that cotton pathogen acquisition by the SGSB was not sufficient to determine whether the insects were disease vectors of the opportunists.

An Opportunistic Pantoea sp. Isolated from a Cotton Fleahopper That Is Capable of Causing Cotton (<i>Gossypium hirsutum</i> L.) Bud Rot

“…Our results showed that strain CFH 7-1R that was isolated from a cotton fleahopper is capable of causing boll rot via simulating stink bug transmission [21]. We are currently testing the possibility that cotton fleahoppers can directly transmit the opportunistic CFH 7-1R into buds and young bolls.…”

“…The beans were replenished every two to three days. For microbe transmission testing, adults were caged over fruiting branches using a styrofoam cylinder enclosed with a section of nylon mesh hose fitted over the cylinder and fruiting branch stem and tied at both ends after three fleahoppers were placed in a cage constructed using methods described in Medrano et al [21]. After 7 d the insects were removed from the cages and harvested (see Isolation of Microorganisms from Insects and Cotton).…”

Salivary Proteins ofLygus hesperus(Hemiptera: Miridae)

“…Little is known about the mechanisms of P. ananatis horizontal transmission, but insects are thought to vector the bacterium. It has been isolated from the guts of Alotartessus iambe (Matsumura) (Hemiptera: Cicadellidae), Glyphodes pyloalis Walker (Lepidoptera: Pyralidae), Pseudatomoscelis seriatus (Reuter) (Hemiptera: Miridae), Nezara viridula (L.) (Hemiptera: Pentatomidae), and Frankliniella fusca (Hinds) (Thysanoptera: Thripidae) (Takahashi et al 1995, Watanabe et al 1996, Wells et al 2002, Bell et al 2007, Medrano et al 2009). However, F. fusca is the only conÞrmed insect vector of P. ananantis (Gitaitis et al 2003).…”

Pathogenic aspects ofPantoea agglomeransin relation to cotton boll age andDysdercus cingulatus(Fabricius) transmitting seed and boll rot in cotton germplasm

“…Bacterial strain (Sc-1R) recovered seeds and lint of those bolls where insect feeding signs were pronounced. Medrano et al (2009a), hypothsizing two bacterial (Pantoea ananatis and Klebsiella pneumonia) and one fungal pathogen (Nematospora coryli) might be an opportunistic disease pathogen, southern green stink bug (N. viridula) were fed on green beans contaminated with variants of Pa-1R and Kp-1R. Healthy bolls were caged with contaminated insects for two weeks.…”