agricultural pest cactus fast-spreading food fruit glochids green fruit green. moisture introduced nopales opuntia paddle cactus platyclades prickles prickly pear prickly pear cactus fruit spikes spines textures abundance abundant agricultural-pest edible edible-prickly-pear fruiting green green-fruit Indian-fig moisture opuntia-ficus-indica paddle-cactus perennial prickly-pear prickly-pear-cactus-fruit red ripe ripe-fruit weed